Jump to content

More RAM slows system?


Grogerf

Recommended Posts

Hallo Folks :P When I built this machine six months ago DDR2 RAM was expensive - so I settled for two 512M sticks of 533 MHz DDR2 RAM :wacko: Recently the price has dropped & I bought 2 1G sticks of 667MHz DDR2 RAM for less than the price of the original 1G B) When I first installed the new RAM I remove the 'old' RAM and only had the 2 x 1G sticks of 667MHz DDR2 installed & the machine seemed a lot faster :worthy: :clap2: .An hour or so later I added the 2 x 512M sticks of 533 MHz DDR2 RAM in slots 3 & 4. The BIOS recognises that there is now 3G of DDR2 RAM available and shows it as 533MHz. However the machine seems as if it is running slower than when it had only 2G of 667 MHz RAM installed :thumbsup: . Could this be so? :w00t: Is there an objective speed test to use with Linux that I could use to check this out?Looking forward to furthering my knowledge :o Grogerf

Link to comment
Share on other sites

If you mix memory speeds the computer will clock down to the lowest speed. So, your real-world experience verifies this is happening it would seem.

Link to comment
Share on other sites

It's been my experience too when mixing speeds of RAM that the machine seems slower. Sell the old RAM and buy more of the new stuff! :thumbsup:

Link to comment
Share on other sites

If you mix memory speeds the computer will clock down to the lowest speed. So, your real-world experience verifies this is happening it would seem.
Yep, exactly. Pull out those DDR533 and leave the two DDR667 in it, there you will have your speed back again. :thumbsup: And the sun shines and shines, isn't this a wonderful world ?
Link to comment
Share on other sites

Hallo Folks :D When I built this machine six months ago DDR2 RAM was expensive - so I settled for two 512M sticks of 533 MHz DDR2 RAM :) Recently the price has dropped & I bought 2 1G sticks of 667MHz DDR2 RAM for less than the price of the original 1G :D When I first installed the new RAM I remove the 'old' RAM and only had the 2 x 1G sticks of 667MHz DDR2 installed & the machine seemed a lot faster :( :( .An hour or so later I added the 2 x 512M sticks of 533 MHz DDR2 RAM in slots 3 & 4. The BIOS recognises that there is now 3G of DDR2 RAM available and shows it as 533MHz. However the machine seems as if it is running slower than when it had only 2G of 667 MHz RAM installed B) . Could this be so? :hmm: Is there an objective speed test to use with Linux that I could use to check this out?Looking forward to furthering my knowledge :thumbsup: Grogerf
I don't buy the theory that a difference of 133 MHz in clock speed would slow down your PC to the point where you would notice it greatly.Check the BIOS and make sure that the timing for both RAM modules are in sync with each other or change it to match it as close as you can.In addition, you may not be running in dual-channel mode. You should install those 4 memory modules according to your MB specifications so that they are installed in dual-channel mode configuration. Often times, the DIMM slots are color coded to let you know which pair to install in matching sets. Edited by Tushman
Link to comment
Share on other sites

There you've said something Tushman : it just keeps me thinking about it. If he wants all 4 RAM sticks to be used, it would be worth it to try what you've suggested. :hysterical:

Link to comment
Share on other sites

I don't buy the theory that a difference of 133 MHz in clock speed would slow down your PC to the point where you would notice it greatly.Check the BIOS and make sure that the timing for both RAM modules are in sync with each other or change it to match it as close as you can.In addition, you may not be running in dual-channel mode. You should install those 4 memory modules according to your MB specifications so that they are installed in dual-channel mode configuration. Often times, the DIMM slots are color coded to let you know which pair to install in matching sets.
Hallo Tushman ;) ,Thanks for your insight. The RAM modules are installed in the slot pairs as advised by the Motherboard specifications - I checked this point before installing the new RAM :hysterical: They are clearly colour coded and I set the faster RAM in first pair of slots. The slower pair of modules were put into the second pair of slots.The BIOS recognises the RAM as DDR2 and reports it as such, it automatically detects memory specifications and capacity. It reports the speed of all the RAM at 533MHz when the two 533 MHz modules are installed, but did show the 667 MHz RAM at 667MHz when there was no other RAM installed. I don't know how to ensure that the timing of the Modules is in synch - the advanced BIOS settings don't seem to allow for this. However I'll check & get back if I can find it.The MB manual does advise that all modules should be of identical brand, size and speed. From what I can see the two types of module use different chips.I'll try again with just the 667 MHz RAM installed - after all there is twice the capacity in these modules of the capacity of the slower modules.Grogerf
Link to comment
Share on other sites

I don't know how to ensure that the timing of the Modules is in synch - the advanced BIOS settings don't seem to allow for this. However I'll check & get back if I can find it.
Grogerf, I don't know what motherboard you have, look in the advanced settings for SPD timing. What specific brand & model are you using?
Link to comment
Share on other sites

List the entire setup. RAM and mobo. What the current settings and voltages are. On a side note I doubt you really need the extra 1 GB over the 2 you already have unless you are heavy into video processing.

Link to comment
Share on other sites

On a side note I doubt you really need the extra 1 GB over the 2 you already have unless you are heavy into video processing.
Amen. And may I add, even if the extra 1 GB were 667.What's the distro you are using? Edited by b2cm
Link to comment
Share on other sites

On a side note I doubt you really need the extra 1 GB over the 2 you already have unless you are heavy into video processing.
No, he started with 1 GB and then added 2 GB later. There are other reason to add more memory besides just video processing such as video gaming; CAD/CAM applications, etc. Unlike Win9.x, XP is a NT based OS and thrive on more memory. It's water under the bridge anyway - he's already purchased the additional 2 GB memory. Edited by Tushman
Link to comment
Share on other sites

Grogerf, I don't know what motherboard you have, look in the advanced settings for SPD timing. What specific brand & model are you using?
Hallo Tushman B) ,I've posted the system details on the Forum :D -- you can see them if you click onto my name at the top of a posting :lol: :) I've just gone through the Motherboard user manual and can't see anything about SPD timing - I can see how to adjust the voltage on the RAM and this is untouched - running on normal setting (I intend to leave the voltage this way).Thanks for your interest :D Grogerf Edited by Grogerf
Link to comment
Share on other sites

List the entire setup. RAM and mobo. What the current settings and voltages are. On a side note I doubt you really need the extra 1 GB over the 2 you already have unless you are heavy into video processing.
Hallo FuzzButt :) I really did notice the difference when I installed the new RAM :lol: it was noticeable on opening programs and particularly when scanning :D B) The RAM and motherboard are listed in my details :D :D Grogerf
Link to comment
Share on other sites

Amen. And may I add, even if the extra 1 GB were 667.What's the distro you are using?
Hallo b2cm :D Yes the addition was really noticeable - on opening & closing programmes, moving files & especially so when scanning :lol: The distro is Mandriva 2007.1 - as noted in my details :) :D When I put the original two 512MB sticks of 533 RAM into the second pair of slots the speed advantage seemed to diminish and things seemed back to what they were before with 1G of 533 MHz RAM installed - when I remove them the system seems to speed up. Maybe it's the speed difference in the RAM that I'm seeing rather than a limitation due to the total amount of RAM installed B) Grogerf
Link to comment
Share on other sites

I've just gone through the Motherboard user manual and can't see anything about SPD timing - I can see how to adjust the voltage on the RAM and this is untouched....
You don't need to change the voltage setting unless you plan on overclocking it. Not all BIOS will have a setting called "SPD" - I mentioned that as one possibility because I didn't see what motherboard you have. However, I'm a little surprised there is no setting to change the CAS timing for the memory modules. One thing you may want to think about is updating your BIOS. I noticed on Gigabyte's website there is a BIOS update (listed as F6) that addresses "DDR2 memory compatibility" issues. What is your current BIOS version?http://www.giga-byte.co.uk/Support/Motherb...=GA-M55plus-S3G Edited by Tushman
Link to comment
Share on other sites

Maybe it's the speed difference in the RAM that I'm seeing rather than a limitation due to the total amount of RAM installed B) Grogerf
People don't understand that a difference of 133 MHz in memory clock speed would equate to almost nothing in real life application terms. I think it's really grasping at straws to blame it on such a small difference. I just skimmed over the manual for your particular motherboard which I downloaded from Gigabyte's website. I found out some information which you should consider.As I suspected in my first reply above, you may not be running dual channel mode. Even if you have the 4 memory modules paired & installed correctly in the 4 slots, there is one specific catch.http://aycu17.webshots.com/image/16096/200...45236503_rs.jpgThe above states specifically that if you want to use 4 memory modules in dual channel mode configuration, all 4 of them need to be identical size, speed, and timing. Therefore in your situation, since the 2nd pair of memory you recently purchased is of different size & speed - you will not achieve dual-channel speeds.Secondly, your motherboard has a BIOS setting called MIT (Motherboard Intelligent Tweaker) See screenshot below. When I talked earlier about changing the timing for the memory modules, This is exactly what I was talking about. The default value is 4 - change it according to your memory specifications. If one pair is 4 and the other pair is 5, use the higher value.http://i5.photobucket.com/albums/y182/tush...igabyte_CAS.jpgFor some reason I cannot get a direct link to the images. You'll have to click on the links for the images. Edited by Tushman
Link to comment
Share on other sites

Tushman.....A loss of 133 MHz, for a 667MHz system anyway, would be 20%. I think that would be more than a noticable difference, but I may be wrong. I've never put slower modules in a system before. I'd think that RAM, being heavily used by most operating systems, would benefit from every bit of speed boost possible.My $0.02 worth.......Adam

Link to comment
Share on other sites

Tushman.....A loss of 133 MHz, for a 667MHz system anyway, would be 20%. I think that would be more than a noticable difference, but I may be wrong. I've never put slower modules in a system before. I'd think that RAM, being heavily used by most operating systems, would benefit from every bit of speed boost possible.My $0.02 worth.......Adam
It's not a 667 MHz system. That's the speed for just the memory modules alone according to Grogerf.I think the single most overriding factor for the noticeable slow down is the fact he is not running in dual-channel mode. As far as the clock speed difference, once again - I stand by my comment earlier that you't see a noticeable difference. Actually the difference in memory clock speed is 33 MHz. Not the 133 Mhz like I originally thought. As I understand it, dual channel ram was created to reduce the bottleneck at the CPU memory controller because the bandwidth for DDR memory outpaces what the CPU memory controller can process at any given time. And that's why he's seeing the noticeable slow down. The I/O bus clock between the two memory amounts to a 67 Mhz difference - I really doubt that any 32-bit application would be able to take advantage of such a tiny difference. The address controller at the CPU utilitizes a single 64-bit channel while in single channel & that's not going to change no matter how fast the data gets there.ScreenHunter_001.gif Edited by Tushman
Link to comment
Share on other sites

Gigabyte has an overclocking utility called 'EasyTune' (it should be on the drivers CD that came with the motherboard) that you can use to tweak your memory. If you have quality 533Mhz modules, you should be able to overclock it to run at 667Mhz. When you do and see a boost in system performance, then you can conclude that the clockdown is the reason for the slowdown.As for dual channel, the POST would usually indicate if it is enabled. I am pretty sure it is enabled even if you install 2 different pairs of DDR modules, but just check it out.PSI forgot you are using Mandriva. Never mind EasyTune as it is Windows-only.

Edited by b2cm
Link to comment
Share on other sites

People don't understand that a difference of 133 MHz in memory clock speed would equate to almost nothing in real life application terms. I think it's really grasping at straws to blame it on such a small difference. I just skimmed over the manual for your particular motherboard which I downloaded from Gigabyte's website. I found out some information which you should consider.As I suspected in my first reply above, you may not be running dual channel mode. Even if you have the 4 memory modules paired & installed correctly in the 4 slots, there is one specific catch.http://aycu17.webshots.com/image/16096/200...45236503_rs.jpgThe above states specifically that if you want to use 4 memory modules in dual channel mode configuration, all 4 of them need to be identical size, speed, and timing. Therefore in your situation, since the 2nd pair of memory you recently purchased is of different size & speed - you will not achieve dual-channel speeds.Secondly, your motherboard has a BIOS setting called MIT (Motherboard Intelligent Tweaker) See screenshot below. When I talked earlier about changing the timing for the memory modules, This is exactly what I was talking about. The default value is 4 - change it according to your memory specifications. If one pair is 4 and the other pair is 5, use the higher value.http://i5.photobucket.com/albums/y182/tush...igabyte_CAS.jpgFor some reason I cannot get a direct link to the images. You'll have to click on the links for the images.
Hallo Tushman :D ,Thanks again for your reply and explanation about the difference in the RAM specifications :rolleyes: :D . Still 33MHz is still 20% of 166MHz so the percentage difference in speed is still there - no matter what the name :( I was aware of the warning about identical memory modules for dual channel and wondered about this being a problem back in posting #7 :pirate: . The strange thing is that the BIOS reports that dual channel is in operation at 533MHz. :hmm: Found the MIT :pirate: and both pairs are showing the default value of 4 :hmm:I have come up with a solution to this problem :thumbsup: My wife's machine is old & slow and has RAM that is now hard to find & expensive. The motherboard has only two RAM slots - so I can't add RAM it has to be replaced with larger modules and the maximum is 512M :sweatingbullets: Time for a new motherboard & processor in her system :thumbsup: There is no need for graphics manipulation etc. so 1G of RAM and a basic processor will be fine :) Grogerf
Link to comment
Share on other sites

Gigabyte has an overclocking utility called 'EasyTune' (it should be on the drivers CD that came with the motherboard) that you can use to tweak your memory. If you have quality 533Mhz modules, you should be able to overclock it to run at 667Mhz. When you do and see a boost in system performance, then you can conclude that the clockdown is the reason for the slowdown.As for dual channel, the POST would usually indicate if it is enabled. I am pretty sure it is enabled even if you install 2 different pairs of DDR modules, but just check it out.PSI forgot you are using Mandriva. Never mind EasyTune as it is Windows-only.
Hallo b2cm :D ,Yes Easytune is out with Linux :sweatingbullets: - but then so is the BIG expense of an operating system :pirate: and then that other BIG EXPENSE of all the application software to go with it :pirate: :thumbsup: The only real drawback I've found is with OCR software which is 'very average' on Linux & I don't use that very often :) Yes it's that POST response that has me puzzled - when I put the 'old' RAM back into the system I was already aware that it might not work in dual channel mode (see post #7) and decided to give it a go to see what happened :( I was pleasantly surprised to see that the POST responded telling me that it was in dual channel mode - albeit at 533. :thumbsup: The problem came when I started to use the system it seemed that most/all of the speed gain achieved with 2G of memory had 'evaporated' with the mixed 3G set up :rolleyes: Ah well nothing lost - and now I've got part of my wife's new system at effectively no cost :hmm: (using two more of the original 512Mb modules to achieve 2G would have cost more than buying the two new & faster 1G modules - and the new modules are good quality :D )Grogerf
Link to comment
Share on other sites

Yes it's that POST response that has me puzzled - when I put the 'old' RAM back into the system I was already aware that it might not work in dual channel mode (see post #7) and decided to give it a go to see what happened smile.gifI was pleasantly surprised to see that the POST responded telling me that it was in dual channel mode - albeit at 533.
That is normal and to be expected. That is why dual-channel modules are sold in pairs and not in fours. If you want to add another 2GB, make sure it is sold as a pair.What a wonderful solution. That should make your wife very happy. Edited by b2cm
Link to comment
Share on other sites

It's not a 667 MHz system. That's the speed for just the memory modules alone according to Grogerf.I think the single most overriding factor for the noticeable slow down is the fact he is not running in dual-channel mode. As far as the clock speed difference, once again - I stand by my comment earlier that you't see a noticeable difference. Actually the difference in memory clock speed is 33 MHz. Not the 133 Mhz like I originally thought. As I understand it, dual channel ram was created to reduce the bottleneck at the CPU memory controller because the bandwidth for DDR memory outpaces what the CPU memory controller can process at any given time. And that's why he's seeing the noticeable slow down. The I/O bus clock between the two memory amounts to a 67 Mhz difference - I really doubt that any 32-bit application would be able to take advantage of such a tiny difference. The address controller at the CPU utilitizes a single 64-bit channel while in single channel & that's not going to change no matter how fast the data gets there.ScreenHunter_001.gif
I know it is not a 667MHz system. I was referring to the RAM speed.Still, if you look at the original post... the system was using 2GB of RAM @ 667MHz. When he added the extra 1GB of 533MHz RAM, and the system "felt" slower. My understanding in this area (including dual channel) is that all RAM must be running at the same speed. Therefore the system is defaulting to 533MHz. There you have the loss if 133MHz, which I think would be enough for a typical user to notice. Aside from hard drives, the most important factor in the perceived system speed is going to be RAM and CPU cache that runs as quickly as possible. http://en.wikipedia.org/wiki/Dual-channel_architecture
Its ability to produce a bottleneck effect arises when it is unable to keep up with the processor, leaving it with nothing to process while the memory controller is struggling to keep up with the data flow.
That article reads more like it was a CPU bottleneck than a memory bottleneck. I remember reading about dual-channel technology when it was first released.... the purpose was to get data to the CPU much faster than with a single channel configuration. The memory controller is going to work at the speed of the memory, which usually is at best 25% of the processor speed. Getting more data to the CPU faster makes the system "faster" to the end user, much like a faster memory module.Adam
Link to comment
Share on other sites

Getting more data to the CPU faster makes the system "faster" to the end user, much like a faster memory module.Adam
No... it's not a matter of getting "more data to the CPU". The bandwidth stays the same. The clock speed is what changes. People confuse bandwidth for clock speed and think that the higher the Mhz rating will equate to more data being pushed around which isn't always true. At any rate, the chart that posted above states the clock speed between the 2 memory speeds is 33 Mhz - to me that is an very small difference in computing terms. DDR2 memory is so fast & offers so much bandwidth that I really doubt a clock speed difference of 33 Mhz will be noticeable to the naked eye. Edited by Tushman
Link to comment
Share on other sites

the purpose was to get data to the CPU much faster than with a single channel configuration. The memory controller is going to work at the speed of the memory, which usually is at best 25% of the processor speed. Getting more data to the CPU faster makes the system "faster" to the end user, much like a faster memory module.
With dual-channel disabled, the system sees/uses the 4 memory pairs as:1 1Gb DDR667 64-bit @ 533Mhz1 1GbDDR667 64-bit @ 533Mhz1 512Mb DDR533 64-bit @ 533Mhz1 512Mb DDR533 64-bit @ 533MhzWith dual-channel enabled, the systems sees/uses the 4 memory pairs as:1 2Gb DDR667 128-bit @ 533Mhz1 1Gb DDR533 128-bit @ 533Mhz
Link to comment
Share on other sites

With dual-channel disabled, the system sees/uses the 4 memory pairs as:1 1Gb DDR667 64-bit @ 533Mhz1 1GbDDR667 64-bit @ 533Mhz1 512Mb DDR533 64-bit @ 533Mhz1 512Mb DDR533 64-bit @ 533MhzWith dual-channel enabled, the systems sees/uses the 4 memory pairs as:1 2Gb DDR667 128-bit @ 533Mhz1 1Gb DDR533 128-bit @ 533Mhz
Have you read the motherboard manual? Somehow I don't think you would be making that assumption if you did. Edited by Tushman
Link to comment
Share on other sites

That is the vendor's recommendation, not a requirement for dual-channel to be enabled. And if you missed Grogerf's confirmation, with the 4 memory sticks installed, the POST displays a message that dual-channel is enabled, with all 4 clocked to 533Mhz.

Edited by b2cm
Link to comment
Share on other sites

That is the vendor's recommendation, not a requirement for dual-channel to be enabled. With the 4 memory sticks installed, the POST displays a message that dual-channel is enabled, with all 4 clocked to 533Mhz.
That "recommendation" is from the motherboard manufacturer - not the vendor. To me that's an important distinction.I used to think that w/ the dual channel RAM, as long as the pairs matched in density, speed & specs, it would work. Even if the 2nd pair was not the same size. However I think it's case specific according to the motherboard & chipset. As in this case with grogerf, it's probably not running dual channel mode and what he may be seeing in the BIOS setting is that dual channel is simply enabled. Edited by Tushman
Link to comment
Share on other sites

I mean Gigabyte by vendor.Pair1 must have matching modules, otherwise the BIOS will disable dual-channel mode (parallel read/write on the same-colored slots). Pair2 may be of another speed but the 2 sticks must also be a match. If any of the 2 pairs does not have matching modules, the BIOS will disable dual-channel.Yes, you are right. Determination of a 'match' of modules depends on the chipset and the BIOS. So you really cannot tell until you install your memory sticks on your motherboard.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...