It all depends what you have now really If you do upgrade your CPU, you will notice a difference, but how much that difference is can vary greatly. If you are keen on upgrading, then wait until February when price cuts will be made by Intel.
That said, if the rest of the system isn't too powerful, then upgrading only one part will have less of an impact. You may also want to consider adding more RAM or changing your graphics card etc.
Anyway, this is all very vague, so forgive me. In short, you will get a speed bump by upgrading your CPU, but by how much really depends on what kind of system you're currently running.
Edit ~ Having just thought about it, the SS51G/SS51G v2.0 only support 533Mhz FSB, whereas the latest Intel Shuttle support 800Mhz FSB and Hyper-Threading. Have a limited bus like this hampers any performance boost a new CPU would potetially provide
Edit 2 ~ For those interested, Shuttle have recently launched their ST62K 'Zen' XPC. More Shuttles - included a revised, smaller (!) model - are also due for release this year.
i got a 9500pro card which i think is still good enuff, sound wise i am on the mobo crapolla sound till i get the external audigy 2 module, im only asking as im getting low fps in the far cry demo, and in pro evo soccer when every there is a corner kick and screens is full of players the game laggs.
btw dont the new Zen shutle only have a single pci slot an no agp?
as for the 800fsb thing, i got a mobo from an 61G inc comming, but thats to be used in somat else
The Radeon 9500 Pro is a great card, so I wouldn't worry about that after all You don't mention your RAM, but 256Mb should really be a minimum, ideally 512Mb if at all possible (or 1Gb+ if you have money to burn).
As for the Zen, Shuttle have shaved a few centimeters off every side, which means the PSU is external and the AGP slot is gone (contrary to the Shuttle's website specifications). I've yet to read any reviews of it, yet, though, and it should be noted ATI are still relatively new to this SFF area.
Anyway, as for the CPU, if you are going to upgrade, as I say, just wait a little longer if you want the price reductions.
I also made a mistake, or rather Shuttle did. This Shuttle does not have an AGP slot (contrary to their website specifications for this model). Sorry about that. And yes Ch3tan, the ST62K does have an external, fanless, power supply unit (180W).
mem i got is 256x2 crucial 2700 DDR. but shall be upgrading to 512mb x2 sticks soonish.
thanks for lettin us know about the price dropage expected. i have looked at the latest shuttles namely the 75 p4 model but cant really justifi spending much specialy as this one i have has been me most stable pc.
Anyone know how much longer 533Mhz P4's will be availible for? I wouldn't mind sticking a 3.06Ghz HT one in my SB51G. I can't say I need a huge amount more power, but if I can upgrade now an d save myself buying a new Shuttle when I do upgrade, I'd much prefer it. Plus, I'm still running a 400Mhz P4 (1.7Ghz Williamette), so even the 533Mhz part will be a nice upgrade.