Choosing an AMD CPU for Virtualbox

[neilgunton]

Hi, I'm in the process of choosing components for a new development workstation for myself. The host OS will be Debian Squeeze, and I will be running Windows 7 as a guest under Virtualbox. I am trying to decide between the Athlon II X4 640, which runs at 3.0 GHz and has no L3 cache, but only costs $100 on Newegg, and the Phenom II X4 970, which is 3.5 GHz, has L3 cache, and costs $186. I know the 970 is the faster processor based on pure GHz, but what I'm wondering specifically is how useful the L3 cache will be to Virtualbox, when running Windows 7 as a guest from within Debian Linux. Basically L3 cache is useful to processes and threads that share memory - it saves a round trip back out to the main RAM. Someone mentioned to me that this is useful for games, but most Linux processes don't share memory that much. So I'm wondering - would Virtualbox find L3 useful? Anybody know if it's written in such a way that this would give me any real benefits when running Windows 7 as a guest? If it really doesn't matter much then I might as well just go with the cheaper (and cooler) Athlon instead.

Actually, here's an even more interesting comparison - The Athlon II X4 640 3GHz, and the Phenom II X4 820 2.8 GHz. Both are exactly the same price on Newegg ($100) and both are 95W. The Athlon has an edge of 200 MHz, but the Phenom has the L3 cache. Which one would be more useful to running Virtualbox?

Thanks for any insights...

Neil

[squall leonhart]

the phenom ii is the better processor.

[neilgunton]

I know it's "better", but the only real difference between the equivalent Phenom and Athlon processors is the L3 cache. This is really only useful for processes that share memory with each other. I'm wondering specifically whether this aspect would be useful to Virtualbox - is it multithreaded, using shared memory? I'm just not very familiar with how virtualization works under the covers. I've been getting the impression that L3 is most useful for games, just wondering if it's useful to Virtualbox.

I don't play games. This is a development box (LAMP - Linux, Apache, MySQL, Perl) and C++. I also run a MySQL slave which has to keep up with a fairly busy community website. I would give Virtualbox 2 cores when it's running, and probably 4 GB RAM for Windows 7 - not running anything too grand inside Windows, really, though I may at some point need to get whatever Microsoft's latest version of their C++ compiler is, for cross-platform development. Mostly, though, it'll be running IE for website testing purposes, and also my Epson scanner software when I need to use that.

Thanks,

Neil

[Perryg]

I was told by the DEVs that the AMD was good in any case, but the Intel was faster with VirtualBox albeit more expensive.
As for the L3 cache it might make a slight difference, but I doubt you would see the difference IMHO.

[fixedwheel]

Actually, here's an even more interesting comparison - The Athlon II X4 640 3GHz, and the Phenom II X4 820 2.8 GHz. Both are exactly the same price on Newegg ($100) and both are 95W.

i would prefer the L3 cache of Phenom 820

http://www.cpubenchmark.net/cpu_lookup. ... +II+X4+820
http://www.cpubenchmark.net/cpu_lookup. ... +II+X4+640