Core 2 Duo and DDR2-800

[Ryan Norton]

Hey guys,

I've been an AMD person for the past 2 years, but was able to snag an E6400 at wholesale price so I figure that justifies investing in an LGA775 mobo and DDR2. I feel like I've seen a lot of hoopla over DDR2-800 and how the 965 boards NB supports it natively, but I've also encountered stories of difficulty: stuff like RAM sold as DDR2-800/PC6400/whatever SPD timings aren't set that high, or require more voltage than the shipping BIOSes of most Core 2 Duo compatible motherboards deliver (2.1v is what I keep seeing).

So let's say I want 2GB of RAM at DDR2-800 with my E6400. Put overclocking temporarily out of the picture. Am I going to have to find another stick of DDR2 with which to flash the BIOS to a newer version (whatever mobo I go with) so I can change the Vdimm to 2.1v allowing me to change the memory clock to 800?

Man, I feel like just when I understood the DIY/enthusiast PC game over in the AMD world, Core 2 Duo arrived to take all my expertise away! Thanks.

 

[Pabster]

That's only an issue with the Gigabyte DS3 board.

 

[Ryan Norton]

Oh OK, so a DQ6 or P5B, if DDR2-800 were installed, would likely be up and running at that speed with no BIOS adjustments or flashing necessary?

 

[Pabster]

Well it isn't going to run 800 by default. It'll run 533 (2x266). I don't know if the P5B has dividers or not.

You'll need to run 400 1:1 to get it running 800 otherwise.

 

[Mogadon]

Most of the P5B boards shipping don't have the more recent BIOSs and hence don't support conroe out of the box. You'll either need to hotflash the BIOS in another board, use an older LGA775 chip to flash the BIOS or get a replacement BIOS chip from ASUS.

 

[Kougar]

Originally posted by: Pabster
Well it isn't going to run 800 by default. It'll run 533 (2x266). I don't know if the P5B has dividers or not.

You'll need to run 400 1:1 to get it running 800 otherwise.

Um, and why would it not run 800mhz out of the box? That is what RAM dividers are for... For DDR2-800 RAM the mainboard should default to a 2:3 ratio. Find a good OCer, and you can raise the FSB to run 1:1 with DDR2-667 or 800 RAM.

With the kind of RAM I bought (Corsair XMS2 2x1gb, 1.9v, $180) I had no issues with the DS3, although it was more luck than anything. I have heard of some DS3s shipping with a newer "F3" BIOS now though, so it shouldn't be as much of a problem. Usually the voltage hungry stuff is what seems to be causing the majority of issues, and since G.Skill is still selling some of the cheapest voltage hungry PC2-6400 RAM...

 

[Mogadon]

Anyway, In all honesty if you've just forked out $600 - $whatever for your new system the price of adding in a $20 stick of low voltage DDR2 PC4200 is so minimal in comparison with what you've already layed out it really doesn't hurt to get a stick for your piece of mind, then you know that even if your system doesn't boot with the RAM you want you can still flash the BIOS using the cheapo RAM you bought for just such an event.