RAM option question (speed/size tradeoff)

[emblue]

I currently have 2GB of RAM in my system in the form of 2 single 1GB sticks @ 800MHz. I have the option to install a bit more RAM in addition to that in the form of two 512MBsticks @ 667MHz.

Will it be worth it to do so? Will I notice a performance difference? Is getting 1GB more RAM enough of a gain to make up for dumbing down the speed?

Do you need to know more to be able to advise? Please let me know.

Thanks!

 

[Rob Williams]

Hi emblue and welcome to the forums!

To be honest, moving from 2GB of RAM to 3GB isn't going to make a large difference, although moving from 2GB to 4GB could if using a 64-bit OS. Unless you're juggling huge images in Photoshop, or editing videos to re-encode, it's not too important to have a ton of RAM, and generally, unless you have a specific reason for it, adding more to your system isn't going to give you a noticeable gain.

Games can be improved with extra RAM as well though, so it really depends on what you're trying to do. Have you found your system to be slow recently?

To answer your question, the difference between DDR2-667 and DDR2-800 in the real-world isn't going to be easily noticed, if it could be at all (it'd require specific scenarios to see a performance difference). The bigger detriment might be the 1GB-512MB-1GB-512MB configuration. Using mixed-matched densities is fine, but I don't think it's quite as efficient as having all four modules the same size.

 

[Tharic-Nar]

The 2 major concerns here are timings and dual channel.

The speed drop from 800 to 667 will not be that substantial, what you need to take care over is not to mix the 1GB and 512MB on the same channel. Typically, slots 1 and 3 are channel 1, and slots 2 and 4 are Channel 2. The 1GB modules will need to go into slots 1 and 3, and the 512MB modules into 2 and 4. Or vice versa, as long as they don't share the same channel. If you mix the two types on the same channel, you'll run the memory Async, meaning it'll run at half speed. When you boot the PC up, it will say if it's working in dual channel or Async.

The other problem may be that of timings. Things like T1 and T2, CAS, etc. The 1GB modules will be slower, and need relaxed timings (despite the higher frequency), but the motherboard can not operate independent timings for each channel, so it will try and run the faster timings of the 512 modules on the 1GB, resulting in instability. If the modules can take it, all well and good, if not, it may cause the system to crash a lot. If you have access to memory timings, make sure to match them to the slowest (eg, the highest CAS and T latency values). The motherboard should be able to adjust automatically if it's not setup to use manual timings, it's just something to bare in mind.

As far as extra memory is concerned, unless you actually need it, you won't see a huge difference.