[Jasper1006]

Running Vista Home Premium 64 bit with SLI mode enabled. I have purchased 8GB (4x2GB)of DDR2 RAM from OCZ. Using two of my sticks I can boot normally. But when I install all 8GB or 6GB, I go through the POST, but then Vista wont boot, just a black screen. I have tried using all combinations of the RAM sticks to verify they all work, and they DO. I also tried booting from the Vista disk to re-install the OS. But with 8GB installed it wont even let me do that! Any suggestions?? I hate to "waste" 4GB of good RAM.

[Jbasto]

does your mobo takes 8 gigs of ram ? cause if it dont then that is your problem

[Jasper1006]

The manual says it supports up to 8 GB.

[calvin-c]

And if it completes the POST then you can be assured that the mobo does, in fact, support 8GB of RAM. (Manuals have been known to be wrong.)

[Jasper1006]

It DOES complete the POST. So I can be sure the mobo supports 8GB. What would be my next step in solving this? Oh, my BIOS is current as well.

[Berzerk]

have you verified that all your dimms are working?.

EDIT

might help if you tell us what motherboard you are using and exact model name of your memory.

[jonmcc33]

Have you run Memtest86 with all four DIMMs installed?

Also, what motherboard or brand of PC do you have? Have you tried bumping the vDIMM by 0.1V to see if it helps? What ratio is your RAM running to your FSB?

[Jasper1006]

I have 4, 1GB sticks that work. And are recognized. Same brand (OCZ). This confirms the all four DIMM's are working? I have not ran any memory testing software. It was a Cyberpower PC Gamer Infinity 8300 from Newegg which I swapped something things out on. The RAM is running at 800Mhz and the FSB is 1333. I do not have an option to change voltages except on the CPU.

FYI...

Intel Core 2 Duo E680 Conroe 3Ghz
MSI P6N SLI-FI mobo (nForce 650i SLI) (AMI BIOS version 2.3)
4GB (2x2GB Kit) OCZ "SLI Ready" DDR2 800 (PC2 6400)
Dual EVGA 8800GTS SSC 640mb 320bit
Dual 500GB SATA HD's (1 x WD Caviar, 1 x Seagate Barracuda)
850W PS (OCZ GameXStream)
Vista HP X64

I am running everything at "stock" speeds...

[jonmcc33]

Download the ISO for Memtest86 and run it?

[jonmcc33]

Memtest86 will not load the OS. You boot to the CD and it will test the memory to ensure it works, just to rule out the possibility that it's hardware related and not the OS.

[Jasper1006]

I have it running right now. Takes a while. The RAM I have is supposed to have ECC. Memtest86 is showing ECC "off". Is this an optional feature(ECC)?

Correction. EPP, not ECC.

[jonmcc33]

It's going to take some time. Why are you using ECC memory? ECC is built into the RAM. You cannot turn it off if it really is ECC memory.

[Rich-M]

You should always check compatibility either at ram maker site or motherboard mfgr site and IU just did. That board is not compatible with any Ocz ram, which is not uncommon BTW. I only use Corsair, Crucial or
Kingston as they actually mfgr ram not just resell it and their sites have configurators I have never found wrong. With ddr2 and up boards, if I cannot match it then I don't buy the ram.

[Jasper1006]

I did actually verify via MSI's website before buying. The link to my mobo...
http://www.msicomputer.com/product/p...LI-FI&class=mb

OCZ Technology is on the list of supported memory. I can boot with any combination of 2(4GB) OCZ SLI RAM sticks. But not all 4(8GB) or even 3(6GB). Memtest did not report any errors. I also have 4GB (4x1GB) OCZ Platinum RAM sticks of the same speed that work fine. Meaning that all 4 slots are working fine. All of the RAM I have is working fine.
What if I disabled SLI and removed one of the video cards? Could this be some type of conflict with Vista and SLI?

[Rich-M]

Ocz is listed but not all ocz and if you go into Ocz there it shows only some real old 865 and 875 chipset boards supported, but not your board or anything near it.