I've got 2x512mb and 4 ram slots, what's the best way to increase my ram?

[Caxus]

The reason I ask is because i'm not sure if putting two more identical 512's in there will give me some kind of performance hit because i'm using 4 sticks. Would it still be dual channel on an Asrock 939 dualsata2 or would I have to buy two 1g sticks to still be dual channel? I don't have the manual with me but i remember that two of the slots were one color and the other two were another color which would lead one to believe that you can still have dual channel with 4 sticks.

Is there any advantage to getting two fresh 1gb sticks and tossing the old ones?

[kryyst]

I would put in 2x1 gig sticks into your primary bank and move the 2x512's to your secondary bank. Usually dual channel is in 1 bank and not between banks.

Then later if you want more then 3gig's of ram replace the 2x512 with 2x1 giving your 4 gigs total, which is your max.

[edcentric]

On some mobo you will run slower with four sticks than with two. Usually with two you can run 1T, and with four you have to run 2T.
Not the end of the world.
Buy 2x1GB and run some un-buffered sandra benchmarks yourself. I'll be that you don't see more than a few % difference between configurations.

[GrayFox]

Ive been told If you have a first gen Athlon 64 clawhammer if you use more then 2 sticks of ram.it forces it down to DDR 333. (Most newcastles don't have this problem anything newer doesn't either).

[Caxus]

I would put in 2x1 gig sticks into your primary bank and move the 2x512's to your secondary bank. Usually dual channel is in 1 bank and not between banks.

Then later if you want more then 3gig's of ram replace the 2x512 with 2x1 giving your 4 gigs total, which is your max.So if I bought 2x1 gig sticks would they have to be the same brand or anything or should i just look for something with similar timings?

[Caxus]

This is from my motherboard's manual.
_______________________________________________________________
2.3 Installation of Memory Modules (DIMM)
939Dual-SATA2 motherboard provides four 184-pin DDR (Double Data Rate)
DIMM slots, and supports Dual Channel Memory Technology. For dual channel
configuration, you always need to install identical (the same brand, speed,
size and chip-type) DDR DIMM pair in the slots of the same color. In other words,
you have to install identical DDR DIMM pair in Dual Channel A (DDR1 and
DDR2; Blue slots; see p.8 No.7) or identical DDR DIMM pair in Dual Channel B
(DDR3 and DDR4; Black slots; see p.8 No.8), so that Dual Channel Memory
Technology can be activated. This motherboard also allows you to install four
DDR DIMMs for dual channel configuration, and please install identical DDR
DIMMs in all four slots. You may refer to the Dual Channel Memory Configuration
Table below.
Dual Channel Memory Configurations
DDR1 DDR2 DDR3 DDR4
(Blue Slot) (Blue Slot) (Black Slot) (Black Slot)
(1) Populated Populated - -
(2) - - Populated Populated
(3)* Populated Populated Populated Populated

* For the configuration (3), please install identical DDR DIMMs in all four slots.
_____________________________________________________________

Do you think i need to heed the part after the asterisk or should it not matter as long as the timings are similar?

[IndigoRed]

Normally, you buy 2 sticks from the same place they will be the same. Matched pairs are old school and really don't apply. If you mean same as the two you currently have, no, they don't have to be from the same manufacturer.

[Thrax]

You have 2x512 now. You can add another 2GB in the form of 2x1GB in the remaining slots. As long as you buy the same brand/speed/model in both sticks when purchasing your new RAM, you can call it a matched pair. The whole "Matched pair" advertisement thing is 98% BS.

Now here's the thing:

Because you have 512mb sticks, you're going to be losing some speed because the bank interleave (http://en.wikipedia.org/wiki/Interleaved_memory) will be sized differently between the 512mb ICs and the 1GB ICs on your new sticks. You should make up most of the deficit, if not exceed the deficit by sheer RAM capacity, however.

Lastly, 4 sticks might just plain not work. The A64 memory controller often hates four sticks.

[lemonlime]

San Diego cores should be fine with four sticks @DDR400, but this is assuming they are all matched and don't add up to more than 2GB. My Opteron 148 and X2 4200+ ran fine with matching 4x512MB sticks, but it'll likely be another story with 3GB. You may have to manually tweak the timings and reduce the frequency to get it stable. As Thrax mentioned, matching is key--it'll be difficult to find 1GB varieties similar to your Corsair XMS modules--and impossible if they are the lower latency CAS2 dimms.

The safest bet would be to sell off the 2x512MB modules and just pick up a 2GB kit (2x1GB). You'll benefit from 1T command timing as mentioned above and better overall system performance. The memory performance increase would likely outweigh the benefits of an extra 1GB of ram.