Memory on Dell Dual Core Machine

[spyros78]

Hi all,

not sure how to find the answer to this. I have two pairs of memories. A pair of Samsung 512MB DDR at 444MHz and a pair of Kingston 1GB DDR at 667MHz.

I know that if I put both pairs in, my machine clocks at the lowest speed. So, is it better to install only the Kingston memories and have 2GB of memory at 667MHz or put the Samsung pair as well and have more memory but at lower speed?

Many thanks.

[jeffy]

If you have some money, buy two new 2GB kits (2x1024MB matched DualChannel kit) if your Dell computer supports it. BTW, I assume you are speaking about DDR2, not DDR1. The memory is so cheap now that you should have no trouble finding good modules at least 667MHz or higher for a reasonable price.

Or get exactly the same Kingston modules again. Check before purchase that your board can handle 4GB without a problem.

Or install the 2GB Kingston modules only (667MHz is the advantage).

Depending on the OS, you might not be able to use all of the 4GB installed.

In the end, the choice is yours.

[spyros78]

Jeffy,

I am talking about DDR2 and my board can take up to 8GB. I probably will get another pair at some point. Why do you believe it is better to have less memory at higher speed than more memory at lower speed?

Many thanks!

[jeffy]

Jeffy,

I am talking about DDR2 and my board can take up to 8GB. I probably will get another pair at some point. Why do you believe it is better to have less memory at higher speed than more memory at lower speed?

Many thanks!
Memory bandwidth and the latency play the key role.
These graphs for example, some real world gains also:
http://www.behardware.com/articles/623-10/intel-core-2-duo-test.html

If you don't care too much about a few percent speed improvement and if your config 2x1GB + 2x512MB is stable, then you can leave both the modules there.

[Blue_MiSfit]

That's an interesting article you linked. It's contradictory to anything I've ever read, which has shown little to no performance difference between (for example) DDR2 533 and DDR2 800.

I know Photoshop is supposedly memory bandwidth bound most of the time, as are most high resolution image processing operations. Of course, video is still CPU bound, but hmm... I might have to do some research and testing now..

~MiSfit

[spyros78]

That's an interesting article you linked. It's contradictory to anything I've ever read, which has shown little to no performance difference between (for example) DDR2 533 and DDR2 800.

Which suggests that more memory at lower speeds might be better than less memory at higher speeds. I'm also thinking more memory means more things can be cached. I'm not entirely sure you can tell the difference in performance though jeffy's article does make a point.

sp.

[Blue_MiSfit]

Sure - to a certain extent anyway. RAM sitting there un-used doesn't help anyone - no matter how fast or low latency it is.

Conventional wisdom (recently) has been that RAM speed doesn't matter at all anymore, but this article says otherwise..

~MiSfit

[saint-francis]

For all practical purposes there seems to be little or no value in having faster memory with lower latency. I have experimented with my system enough to satisfy my own personal curiosity on this matter. At this point I just keep my memory at 1:1 with my fsb for overclocking purposes and lower the latencies as needed as the memory speed reaches it's limits. In many experiments with video encoding there has been absolutely no difference in speed. Maybe something like photoshop could benefit, I don't know as I rarely use it. Also using more than 2 GB of RAM seems to be completely useless unless you use Vista 64 bit and you often open a great deal of applications so superfetch can be of any use. Otherwise all benchmarks show either absolutely no performance gain at all or a performance decrease since it's difficult to get low latencies with so many sticks.