More RAM slows system?

[FuzzButt]

This is pretty simple. A loss in 20% of the memory speed will also relate to a 20% less memory bandwidth. You simply cannot move the same amount of data thru a slower bus.I have 2 nearly identical PC's here. One has a 400MHZ buss and a 2.8GHz P4 and the other has a 800MHz bus and a 2.8GHz P4 with HT. The difference in usability is staggering. Even with the Hyperthreading disabled the 800 smokes the 400 in every application I can throw at it. Both have 1GB of matched DDR RAM. The addition of the slower 533MHz based DDR2 modules is what is slowing your PC down. The easiest and safest solution is to remove them and run with 2GB of the 266MHz stuff. I have 2GB of DDR2-800 in this PC (2.4Ghz Core2 Duo) and the addition of a 3rd GB since I had it did not help XP one bit. With Linux you might see the difference. As B2cm put it above the RAM is running in dual channel treating all 4 modules the same. Using the lowest common denominator. Basically the memory controller cannot run one pair at a different frequency than the other in dual mode. Essentially asynchronous.

[Grogerf]

This is pretty simple. A loss in 20% of the memory speed will also relate to a 20% less memory bandwidth. You simply cannot move the same amount of data thru a slower bus.I have 2 nearly identical PC's here. One has a 400MHZ buss and a 2.8GHz P4 and the other has a 800MHz bus and a 2.8GHz P4 with HT. The difference in usability is staggering. Even with the Hyperthreading disabled the 800 smokes the 400 in every application I can throw at it. Both have 1GB of matched DDR RAM. The addition of the slower 533MHz based DDR2 modules is what is slowing your PC down. The easiest and safest solution is to remove them and run with 2GB of the 266MHz stuff. I have 2GB of DDR2-800 in this PC (2.4Ghz Core2 Duo) and the addition of a 3rd GB since I had it did not help XP one bit. With Linux you might see the difference. As B2cm put it above the RAM is running in dual channel treating all 4 modules the same. Using the lowest common denominator. Basically the memory controller cannot run one pair at a different frequency than the other in dual mode. Essentially asynchronous.

Hallo FuzzButt ,Thank you for your advice I've decided to remove the 1G of 533MHz DDR2 RAM and to use it to re-build & upgrade my wife's machine. This will improve the responsiveness of my machine by taking out the slower RAM and improve my wife's machine (which is running a slow processor with 250M of RAM) out of sight All I'll have to buy is a motherboard and processor Talk about two birds with one stone Grogerf