I am starting this thread to stir up discussion. I already have my own opinions on this matter.

So if you had to choose from say 2 gigs of DDR2 1066 and 4 gigs of DDR2 800. What would you choose?

 I would choose the 2 Gigs of DDR2 1066 if runing xp, 4 gigs if on vista. (depends what your cpu and mobo is designed to run at)

DDR2 800 - Data Tranfer Per Second: 800 Mil - Peak Tranfer rate: 6400 mb/s

DDR2 1066 - Data Tranfer Per Second: 1066 Mil - Peak Tranfer Rate: 8533 mb/s

My personal opinion on this is it would depend on usage. If building a box for a family member who only uses e-maill and office apps, I would go with more RAM as it would add longevity to the machine. On the other hand, any usage that even smells of performance and I would go with faster RAM.

In the scenario I quoted, I wouldn't really worry about Vista. More is certainly better, but Vista runs fine with 2gb.

I would'nt I would go with 4 gigs of 1066 period ram is one of the most important things from my point of view I think I'd ene drop my cpu a clock lvl for the 4 gigs and oc my cpu to make the difference I am still running my athlon x2 at 4800 as long as you have a decent cooler (http://www.newegg.com/Product/Product.aspx?Item=N82E16835106080) with w thunderblade 120mm for 50 bucks drop 100 of your cpu oc it to make up the diff then get the 4 gigs to split the difference in the ram price seems the best way to go to me

 I recently upgraded from 2GB to 4GB, but that was purely for my own reasons.  The 2GB runs fine, but I wanted 4GB so I could turn my page file off.  You won't see any performance differences between the 2GB and 4GB (except in Windows XP, or Vista 32-bit, where it's actually been documented you might see a slowdown running 4GB due to memory addressing problems).

rapid1:

I would'nt I would go with 4 gigs of 1066 period ram is one of the most important things from my point of view I think I'd ene drop my cpu a clock lvl for the 4 gigs and oc my cpu to make the difference I am still running my athlon x2 at 4800 as long as you have a decent cooler (http://www.newegg.com/Product/Product.aspx?Item=N82E16835106080) with w thunderblade 120mm for 50 bucks drop 100 of your cpu oc it to make up the diff then get the 4 gigs to split the difference in the ram price seems the best way to go to me

For you yeah, but for a low performance home user, the added RAM speed wouldn't mean a thing. IF there is a difference in e-mail and MS Word between 1066 and 800 it would have to be nano seconds. The added RAM would extend the useful life of the machine. Just my take....

1nteljunki3:

 I recently upgraded from 2GB to 4GB, but that was purely for my own reasons.  The 2GB runs fine, but I wanted 4GB so I could turn my page file off.  You won't see any performance differences between the 2GB and 4GB (except in Windows XP, or Vista 32-bit, where it's actually been documented you might see a slowdown running 4GB due to memory addressing problems).

You must be using Linux. Turning off the page file in any Windows is a bad idea for two reasons. First. software bugs and poorly written software can cause system crashes if it doesn't find a page file. Second. Turning it off prevents any unneeded data in RAM from being paged out and taking up space that could be used for disk cache hurting performance. This can be particularly true in games. Also, Many "good" programs reserve page file space and when they don't find it can crash or slow down. The benefits of turning off the page file are few and usually only single apps. When you start multi-tasking they often disapear.

There has been much debate on this subject. I base my own page file implementation on the advice of older and wiser people who have been around longer than me. (Although after 20 years, those guys are getting fewer and fewer)