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upgrading ram 667 to 800mhz

Posted: Mon Dec 10, 2007 5:04 am
by thomas565
Hi

My thinkpad will come tomorrow and I am about to order RAM. I am thinking of upgrading 1gb ram from the standard pc2-5300 ddr2 667 mhz to 4gb pc2-6400 800mhz (for example, also note the comment from a buyer there: http://www.newegg.com/Product/Product.a ... 6820227251). (I will also wipe out vista64 and put suse64 10.3 on.) Can I change the clock speed and the latency of the ram in the bios to these 800 mhz? I dont want to overclock CPU or anything, just use a 800mhz ram with its supported clock speed of 800mhz or/and set latency to lower levels.

Thanks Toby

Posted: Mon Dec 10, 2007 6:58 am
by aaa
No, 800 mhz ram is not supported in spite of the 800mhz fsb. It will work (at 667) though. You should be able to use software to get lower latency, assuming it doesn't do so automatically.

Posted: Mon Dec 10, 2007 10:52 am
by madcow
Might be cheaper to get the PC5300 RAM. You can get 4 G of RAM for $80 from new egg.

Posted: Mon Dec 10, 2007 7:09 pm
by aaa
Yes, I would just look for cl4 667.

Posted: Mon Dec 10, 2007 10:52 pm
by thomas565
but I would be willing to pay $30 more for CL3; a CL5 800 operated at 667! ?

T

Posted: Tue Dec 11, 2007 5:46 am
by aaa
Problem is CL5 800 most likely will only do CL4 667 automatically, or even CL5 667 (it probably doesn't say what setting's it'll downclock to on the label). So there is nothing special about it. In fact, if you do the math, CL4 at 667 is a shorter latency than CL5 at 800:
5/400 > 4/333

The pattern of ram is that usually the total latency in nanoseconds stays about the same across different speeds. CL3/667 is alot less time compared to CL5/800. So I would doubt that a ram capable of CL5/800 would mean it's capable of CL3/667.

Posted: Tue Dec 11, 2007 9:09 am
by DAH
Who is making a CL3 kit that will fit my T60p? 200 pin seems to be stuck at CL5.

Posted: Wed Dec 12, 2007 7:54 pm
by eyecon82
if we have a 800mhz fsb, why won't it work?

Posted: Wed Dec 12, 2007 8:33 pm
by aaa
Because Intel only included support for 667 ram in the chipset. As for why, I'm thinking it's because it has dual channel: 2x667 > 800. No need.