More memory = SLOWER?!?!

[WaOnFiRe]

Hello all,

I have a problem with someone's else PC. He have an ASUS K8N motherboard, 1536Mb DDR400 (3 DIMM), AMD Athlon 64 3500+ CPU... He find his computer to be slow. So he tested it with a benchmark program called TestLab.

Here's the pic of the results:

512Mb = 115 score
1024 = 97
1536 = 42.

So he was right, what's the problem you think? It's all DDR400 memory but not the same brand. When he test them each one individually, he get the same 115 score. It's when he begin to add more RAM that it slow down. He updated to the latest BIOS (1010) and ti didn't helped.

I don't know what to tell him.

 

[Ampz]

Tell him to get a kit that actually have the same timings. I would suggest only using 2 sticks of either 512 or 1gb. And yes more memory can be slower if you dont need it all. If your using 2x512 at very tight timings and thats all the ram you need for what you are doing then adding ram WILL be slower, the timings will have to be looser. Althgouh if the prog really needs 2gig of ram and u are using 1 the prog will run slower with 1gig so it all really depends on what you are doing.

 

[MrBurns]

Maybe your motherboard has downclocked the memory to DDR333. This is normal when you use 3 modules on Athlon 64 systems (but afaik only w/ older A64 revisions) because of the Athlon 64 memory controller.

Press Pause at bootuup to see, what you BIOS shows.

 

[brigby]

some motherboards do not respond well to odd memory pairings (ie: 3 modules of varying sizes instead of 2 modules of 512)

generally, for the best performance, you want two dual channel chips of smallish size (2x256 MB sometimes can do tighter timings than larger chips - usually 1GB modules have to be loosened)