I'm trying to decide if purchasing 1066 memory instead of 800 is worth the extra money. The two memory sets I am deciding on are the http://www.newegg.com/Product/Prod [...] 6820231166 and the http://www.newegg.com/Product/Prod [...] 6820231122 .

I will end up slightly overclocking my 9800 GTX GPU, but that will be the only oc.

My motherboard is the GIGABYTE GA-EP35-DS3L and I'm purchasing the Intel E8400 Core 2 Duo. Is 1066 memory really necessary if I'll only be overclocking my GPU?

DDR2-1066 may not run reliably on that mobo (or other P35 boards); I've read lots of cases of it and it happened to me as well. Get the DDR2-800.

The E8400 has a 1333FSB so in order to run 1:1 all you need is DDR2 667. I would say buy some quality DDR2 800 and underclock it to 667 and tighten the timings to around 3-3-3-8 and you will get great performance and save a few bucks. Most memory currently is sold at it's overclocked specifications so a lot of DDR2 800 available is really just DDR2 667 which is rated to run at 800 with higher voltages. Take this for instance, this is CPUZ on my former memory which was sold as DDR2 800 4-4-3-10 2.1v

as with most memory currently available you can see there are several different settings for both JEDEC and EPP

So are you saying it will perform better with 667 instead of 800?

FYI, the fastest memory (in the recent tests) is DDR2 1066 CAS4. This was really DDR2 1200 CAS5 memory tested at those settings. You can see it here:

http://www.newegg.com/Product/Prod [...] 6820313007

If you think it is worth the price, go for it!

Simple answer ; no. Long answer, most DDR2-1066 ram is really only factory overclocked DDR2-800 ram, the voltage being raised from 1.8v to 2.1v or 2.2v to support the higher speed. I wouldn't waste the money on the 1066 ram, but that's only my opinion.

No, what he was saying is that you will probably be able to get better timings with the DDR2 800 if you underclock it to 667 than with DDR2 667. If the timings are the same for DDR2 667 and DDR2 800 clocked to 667, then they will perform the same. The only problem is that it is hard to get advertised 667 timings for DDR2 800 so it's hard to make a comparison before you buy.

I know that you don't think you are going to OC your CPU now, but you might want to in the future. The price differential between 667 and 800 is nominal so I would get the 800. You can run it at 800 and run the memory benchmarks in SiSoftware Sandra Lite and then set it for 667 and tighten the timings and bench again. The real world differences in speed and timings are not that large for the Core2 architecture anyway.

In a nutshell, get the DDR2 800.

4x2GB 1066 C5 OCZ Reapers seem to do just fine @ 1.1Ghz on a reasonable motherboard. If you want some good memory that looks great at a great cost, check them out http://www.newegg.com/Product/Prod [...] 6820227289

+1

DDR2-800 is alot cheaper. Crucial Ballistix Tracer 2GB Kit is $26.99 at Newegg.

Since your processor is running a 1333FSB you are really using DDR2-667 in a 1:1 ratio. To fully utilize DDR2-800 you have to oc your processor to reach 1600FSB. Since you are not planning on ocing I would say stick with the DDR2-800. Since you will be running the DDR2-800 at DDR2-677 you can try tightening the timings for a slight performance boost.

If you have 800 Mhz DDR2 the FSB would have to run at 1600Mhz to get the full bandwidth from the ram......so if your CPU's FSB runs at 1333Mhz why would you get 1066Mhz DDR2 unless you plan to really really OC it

For your combo (which I have also)
The G.Skill is a good deal
http://www.newegg.com/Product/Prod [...] 6820231122

If you insist on higher I was looking at these G.Skill 8000
http://www.newegg.com/Product/Prod [...] 6820231145

both are same price btw

I would go with thse instead
http://www.newegg.com/Product/Prod [...] 6820146731
Cheaper after MIR and lower timings