System comparison - Some help needed please

[Matteus]

I need to upgrade my system, I was gonna start fresh but realised my budget isn't quite as good as I forst thought i've tried overclocking but turns out my current system isn't really up to do so, so I have 2 options, baring in mind I have a limited budget. I can either by a part for a new PC every month for a blisteringly fast PC, which of course could take ages, or, upgrade.

My current setup as it stands is:

AMD 3700+
512mb RAM (3200)
200gb HD
ATI x1650 pro 512mb
450w PSU
A shocking case.

And was thinking to upgrade to the following:

ASRock 4CoreDual-VSTA PT880 Ultra
Intel Pentium D 935 (3.2ghz) Socket 775 FSB800
Kingston 2GB KIT (2X1GB) DDR2 667MHz
And a new case

All this comes to £175 which I dont think is too bad, basically my question is, is there going to be a significant performance boost to warrant doing this? I'm playing games at the moment which are so laggy and thought this would be a good option.

Any thoughts or suggestions would be greatly appreciated.

Cheers.

 

[Matteus]

So would that particualr Core2Duo be better performance wise compare to the Pentium D? Even though the processor has higher Mhz?

And I only said 450w because it's a generic one and rather poo tbh. I'll get a new one me thinks but not just yet.