Very slow system when 8GB is installed vs 4GB

[kkk60091]

with new beta bios P35cds3rAT.f4b from anandtech, my p35c is now working well with 8GB ram. this new bios is dated 06/12/07. I believe GA fixed all the boards, but decided not make all of them available...... only three models had the fixed bios on GA website....

 

[mattropolis]

Had this very problem and just got off the phone with Intel's support. Here's an answer that worked for me:

Basically, any bios for the 965 chipset AFTER 1669 has a problem using 4gb/4-sticks of ddr2. You'll get the horrible slow boots/etc that you mentioned. I know, I was getting them too. Use 2gb, 3gb w/ 3 sticks and everything's fine. Put 4 sticks in and life goes to pot. So, the solution is to ROLL BACK your bios to 1669 (current version is 1687). To roll back a bios, you need to follow a weird procedure for setting a jumper, booting off a cd with the .bio file burned on it, etc. Go to support.intel.com and search for article 023360 on how to 'revert' your bios. You also need to download the old version of the bios. Go to the intel download page for your board, and scroll down to the very bottom after it lists the latest drivers and select the "This product has Previously Released software" link. The download the .bio file for bios 1669. I rolled back and everything went super-fast again with 4 gigs under vista. Nice. In fact, I timed the 3gb boots, and with 1687 - it took ~1:45, but with 3gb and 1669, it takes ~0:45 - sounds like more than one problem...

Alternatively, some folks have found applying the MS patch KB929777 has helped, but didn't do anything for me.

 

[firewolfsm]

Slower can mean different things, try running benchmarks.

 

[VirtualLarry]

To see if this is the infamous cache issue with > 4GB, download and burn a Memtest86+ ISO (v1.7), and check the indicated L1/L2/memory bandwidth scores. Chances are, with 8GB, your L1/L2 bandwidth scores will be much lower, if it is the cache bug. If it is, a BIOS update is needed to fix the problem.