Adding more 'different' memory

[fr0sty]

A while back I got a upgrade package for ocuk and that came with 2GB of OCZ memory (2x1GB). Now im going to get windows 7 and I want more memory now too. The problem is ocuk dont sell the memory I have any more. So...

Can I mix the memory I have now with a similar one leaving me with 2x2Gb of new memory to give me a total of 4GBs, 2x1Gb and 2x2GB

Memory I have now:
http://www.ocztechnology.com/products/memory/ocz_ddr2_pc2_8500_sli_ready_edition_dual_channel

What should I do/get?

 

[Jargy]

Interestingly, I'm in exactly the same position. I'm currently running 32-bit Vista with 2x1Gb (OCZ PC2-8500) and am installing 64-bit Windows 7 after Christmas. I'm looking at similar spec memory, but have got my eye on the 2x2Gb set of PC2-8500 Patriot Viper OCuk are selling. I'm questioning compatibility and mixing memory sizes....

Incidently Frosty, doesn't 2x1Gb and 2x2Gb mean you will have 6Gb?

 

[Plec]

In an ideal world you would match the exact same memory, or get as closer match as possible, to try and eliminate possible conflicts.

Important things to consider are that the 2 different sets will run at the same voltages at the same designated frequency. You will also have to run all 4 stick at the settings of the slower memory timings if they are different.

For example: if you had to mix 8500 memory with 6400 you would have to run the 8500 at the lower 6400 spec - negating the 8500 speed and perhaps its better CAS timings (8500 memory is essentially overclocked 6400.) You would also need to ensure that the 8500 memory would run at the same voltages as the 6400 at 800MHz.

Basically, try to get as close a match as possible if you can’t get the same brand/spec.

 

[underclocker]

Snap!
I bough (from OCuk) 2x2gb PC2 6400 (OCZ2G8004GK) when I switched to Windows 7, at the time I though I would be able to pick up another set when I could aford it. Now its no longer in stock can I use this with my old 2x1gb PC2 6400 (2x2gb and 2x1gb)?

 

[Plec]

Snap!
I bough (from OCuk) 2x2gb PC2 6400 (OCZ2G8004GK) when I switched to Windows 7, at the time I though I would be able to pick up another set when I could aford it. Now its no longer in stock can I use this with my old 2x1gb PC2 6400 (2x2gb and 2x1gb)?

It's worth a try - just apply the same principle as i mentioned above - i.e. setting the timings to that of the lowest spec memory and make sure that they will both operate on the same voltage.

Keep in mind that you may have to up the MCH (NB voltage) to compensate for the extra strain on the memory controller. If the system is unstable or fails to boot - up this setting 1 or 2 increments.

 

[Jargy]

As an update, I've just installed 2x2Gb of Patriot Viper PC-8500 alongside my 2x1Gb of OCZ Platinum PC-8500. Both work at the same timings and similar volts. I've memtested both sets and all is working fantastically. Just got to install W7 so I can use it now!

 

[Wrekriem]

The only problems I've ever had mixing memory is having to underclock a set to bring everything in-line but you shouldnt even have to do that, there is usually a similar set avaiable from a different vendor, just under a different name. The important parts are the timings and voltage.