To C4 or not to C4, that is the question

No, I don't mean the explosive stuff...

I have an Abit IP35 Pro with 2x1GB Corsair DDR2 PC2-6400 CAS4 (CM2X1024-6400C4) sticks in it. I am getting Windows 7 x64 and also want to re-install Ubuntu x64 and want to get some more memory. However, after a quick look at my favourite e-tailer, I can see that the same sticks I already have cost £61.85 where as the exact same sticks but with slightly slower CAS timings (CAS5 instead of CAS4) are £50.98, almost £11 cheaper!

Now I know that I will probably not see any difference between the two CAS timings, but will mixing the two cause any problems? Should I pay the extra and stick with all of them being CAS4?

Or should I say screw it, it's really not that important and get two cheap 2GB sticks taking me up to 6GB total for roughly the same price as the 2x1GB CAS4 sticks?

Yeah I'd say go for the CAS5 and have 6Gb to play around with. You can manually change your timings to CAS5 if you experience any problems and you won't notice any difference in performance (apart from the benefits of 2Gb more memory :D). Also you might need to bump up northbridge voltages a bit if you are having any stability issues after giving it two more sticks. It really shouldn't be a problem tbh :)

Why not try Wanted and see if anyone can sell you some cheap 1GB sticks, taking you to 4x1GB.

With a E2180 it is unlikely that you can make use of 6GB of ram.