What's the next part I should upgrade?

[Deleted]

CPU: AMD PHenom II x6 1055T - 2.8GHz (Turbo up to 3.2)
GPU: ATI Radeon HD 5770
RAM: 4GB Crucial DDR3 1333 MHz
HDD: 1 Seagate 500gb 5.4k rpm
Motherboard: Gigabyte GA-870A-UD3

This is basically it...I've been thinking about upgrading my HDD to either an SSD or two new HDD's + Raid0. Got any suggestions?
(My windows rating is 5.9 due to the HDD, the rest is 6.9-7.4)

What's weird is that my FPS is VERY unstable.. Sometimes I have everything on max in SW and I can run around with 100-ish steady FPS. The next second it drops like a bomb down to barely 30.
And yes - I do take care of my computer (Defrag, make sure I have no viruses, I clean it with CCleaner etc.) so I do not see why this happens?

[ayako]

It seems good at the moment, no major reason to upgrade, especially if all you play is WoW at the moment. If you want to upgrade, get either a new 7,200 rpm drive or an SSD

[Deleted]

for perfomance your best options would be a faster hard drive(ssd's are expensive but are rediculously quick way faster than any raid setup will ever be), more ram(cheapest option) or switching to a fast quad core(not many games use hex cores and as far as i know turbo does not work in games also even if it does it reduces the speed on 3 cores down to 800mhz to get 3 cores up too 3.2ghz whereas a decent quadcore is running at 3.5ghz at all times on all cores)

depends what you are uing it for, for wow your gpu is more than enough and wow is very dependent on cpu(allthough yours is probably more than enough what sort of fps do you get?), ram and hardrive.

[BicycleMafioso]

Better, faster and more. In regards to storage. That's where I put my vote as well.
Other than that, an aftermarket-cooler and start overclocking. Really.

[Deleted]

It seems good at the moment, no major reason to upgrade, especially if all you play is WoW at the moment. If you want to upgrade, get either a new 7,200 rpm drive or an SSD

All I play is certainly not WoW - I play a lot of Shogun 2 and Crysis 2 at the moment as well.

for perfomance your best options would be a faster hard drive(ssd's are expensive but are rediculously quick way faster than any raid setup will ever be), more ram(cheapest option) or switching to a fast quad core(not many games use hex cores and as far as i know turbo does not work in games also even if it does it reduces the speed on 3 cores down to 800mhz to get 3 cores up too 3.2ghz whereas a decent quadcore is running at 3.5ghz at all times on all cores)

depends what you are uing it for, for wow your gpu is more than enough and wow is very dependent on cpu(allthough yours is probably more than enough what sort of fps do you get?), ram and hardrive.

The thing is that my FPS is very unstable, and that's why I'm a bit confused.. As I said, sometimes I can reach steady 120+, but I also drop down to 20-30 FPS in LESS crowded zones.