Cheapest performance upgrade for my rig

[_Jay_]

Hey guys. My 5 yr old gaming computer has been running really slow for me the past year or so. I recently changed out the mobo and cpu since my last mobo died on me and Microcenter was offering a good combo deal on a CPU/Mobo. But it does not run anywhere near where I think it should be speed-wise and I was looking for suggestions on making it faster. I don't have a big budget so the cheaper the fix, the better. I use it mostly for Diablo 3 atm. The bootup time and time it takes to load programs is what kills me. Seems like it takes forever to open up firefox sometimes and bootup time is about 5 mins to fully loaded desktop.

Can't remember all of the specifics on the hardware but this is what I can recall:

AMD Phenom II X2 560 Black Edition Callisto 3.3GHz Socket (OC'ed to 3.8Ghz)
MSI 880GM-E35 AMD Mobo
4GB Crucial Ballistic DDR3 PC800 (or PC1333 cant remember) Ram
EVGA Geforce 8800GTS 512MB (G92)
250GB Western Digital 7200rpm HDD
Windows XP Pro
Thermaltake PurePower RX 600W PS

The cpu/mobo are the only thing that has been upgraded in the past 5 years. My HDD has about 95GB of free space on it. I tried unlocking the other 2 cores on my cpu but kept getting random reboots so I went back to 2 cores. What will get me the biggest performance boost right off the bat? (If I need more RAM, I will have to upgrade to Windows 7 first right?)

Thanks in advance.

 

[briansun1]

Get a SSD !

 

[_Jay_]

Get a SSD !

Anything I need to look for specifically on a SSD?

I think my mobo has SATAII connections only so does that mean SATAIII SSD's won't work? Does it matter if it's 2.5" vs 3.5" for a Desktop PC? Do I load all programs on the SSD and just use my HDD for media storage only?

 

[Knufire]

SATAIII will work, 2.5" will fit.

Correct on the storage setup.