Is it okay to mix memory sizes such as a 512 MB DIMM + 1 GB DIMM? Both have the same CAS Latency of 4 and are DDR2 PC-4200 533 MHz.

My MOBO is Asus P5GDC-V deluxe. Manual says if it's dual channel, they should be same. But these are single channel and it doesn't say anything about single channel.

They wouldn't work in dual channel as their sizes are different. But you`re OK for single channel.

You'll have better performance if you install them in matching pairs because that will enable dual channel mode. But, as nitroshift said, it should work, just with reduced performance.

Reduced performance of a few realworld %, I would not even look at that.


@ spacesurfer,
The jump from 512 to 1.5GB will make the diference .
Good luck with using them both, it could be posible that you have the set the right speed in your BIOS manual, just keep the lowest speed for that.

Remember my memory is not dual channel. Are you saying even if I don't have dual channel memory, that installing in pairs of same size will enable dural channel mode??

They will mix fine and don't worry about the whole dual vs single issue, it's vastly overrated. Real world benchmarks will show the difference is so small you wouldn't notice the difference. As stated here they show dual channel only offers a 2%-4% difference, meaning even long tasks that take say 10secs, it's not even 1/4th of a second faster. And in your most demanding games you might get 1 fps more at best. In your older games where you'd gain maybe 5fps, you're already well above 60fps so it won't matter.

Personally, I'd put the largest chip in first (which is usually the newest anyways) as the older chip will go bad first, and if it does, you're less likely to use it, meaning less memory errors as it fails. But I'm splitting hairs here.

Thanks for your help guys. I have ordered 1 GB memory single-channel and it's been delivered. I'm just not at home to install it.

Anyway, I hope Vista is happy with 1.5 GB. It was suffering with 512 MB.

I will post if I have questions. I'm sure you guys have the answers here if I have problems.

All right! I installed my memory. System is up and running. The memory score went from 2.9 to 4.5, not bad.

My overall score is still 1.0 cause of the graphics card. But that'll have to wait.