Should I get more RAM?

[lynx]

All this theory is brilliant, but in practice it usually means almost nothing for AMD processors.

Dual channel is fine in theory, it should give you a data path which is 128 bits wide. Except that your pci bus isn't 128 bits wide, the AGP bus isn't 128 bits wide, and the bus to most AMD processors isn't 128 bits wide (Athlon 64 Socket 939 is the exception).

So you've got a 128 bit data bus to your memory controller, and damn all good it will do you because the widest link to other system components is only 64 bits, except for memory to memory transfers. It is possible to devise tests which will show high bandwidth figures, but these are artificial and in practice the theoretical 6.4GB/s bandwidth is nowhere near attainable.

This is one area where Intel chips are getting better performance over AMD chips, because although they still only have a 64 bit bus, by having an 800MHz FSB speed they can take data twice as fast from the memory controller.

[Virtualbody1234]

... my motherboard ...(Asus P4S533-E) but ... I have no motherboard Manual and can't seem to find out on web anywhere.

http://www.asus.com.tw/pub/ASUS/mb/s...4_p4s533-e.pdf

[bigdawgfoxx]

So what are the qualifications exactly. I have a dual channel setup right now...256X2 PC3200 2-2-2-5. If I were to buy another 512 stick for the 3rd slot, what would have to be the same to make it work? Just the PC3200 or the timings also?

[BILLY-THE-FISH]

http://www.asus.com.tw/pub/ASUS/mb/s...4_p4s533-e.pdf

Cheers mate!!

[Snee]

All this theory is brilliant, but in practice it usually means almost nothing for AMD processors.

Dual channel is fine in theory, it should give you a data path which is 128 bits wide. Except that your pci bus isn't 128 bits wide, the AGP bus isn't 128 bits wide, and the bus to most AMD processors isn't 128 bits wide (Athlon 64 Socket 939 is the exception).

So you've got a 128 bit data bus to your memory controller, and damn all good it will do you because the widest link to other system components is only 64 bits, except for memory to memory transfers. It is possible to devise tests which will show high bandwidth figures, but these are artificial and in practice the theoretical 6.4GB/s bandwidth is nowhere near attainable.

This is one area where Intel chips are getting better performance over AMD chips, because although they still only have a 64 bit bus, by having an 800MHz FSB speed they can take data twice as fast from the memory controller.

I've seen a couple of benchmarks where they got a whopping 6% gain in overall performance with dual channel enabled, but most benchmarks only show how much faster your memory becomes and nothing about what you actually gain.

I think you might get something out of it tho', but you get a bigger boost from enabling 4 bank interleaving if you haven't, for instance. If that's an option on your mobo.

[Snee]

So what are the qualifications exactly. I have a dual channel setup right now...256X2 PC3200 2-2-2-5. If I were to buy another 512 stick for the 3rd slot, what would have to be the same to make it work? Just the PC3200 or the timings also?

According to one of those links I posted ( ! ) "the speed characteristics" should be the same.

Otherwise it gets slowed down to the level of the slowest stick. But that's when talking about the clockfrequenzy.

I think, tho', that it's the same thing with the memory timings, if they are set to auto. Otherwise, if you've tweaked them, you should watch out for instabilities if the new stick can't handle the timings set for the other sticks.

So for it to be totally stable, my theory is that the timings must be set to something the slowest chip can handle.

[Skillian]

Well the extra stick went in fine, and it all works in dual channel.

Used the same Crucial memory, same timings.