I recently (and generously) donated my 2 year old home built rig to my sister who was badly in need of a working computer. It has a 1.86 C2D, 2 GB RAM, Gigabyte S3 mobo, 8800 GTS 320 graphics card, etc. I would like to take a step up from that (doesn't have to be a big step) with a new partial system build. Luckily I have a case, HDD, DVD, fans, and a modular Corsair 520w PSU.
What I would like a hand with is figuring out the best use of my money since I haven't been closely paying attention to new releases and prices on chips, graphics cards, etc. I guess my specific questions are the following:
What is the best buy in CPUs right now? The rig does a lot of gaming, and to a lesser extent graphics processing when my girlfriend's mac is tied up and she needs to do some side work.
Graphics cards I have not paid much attention to as of late. What would be a step up from the 8800GTS 320MB without getting too pricey?
Am I going to be able to transplant the 520w Corsair I have, or is anything I would be looking at going to pull too much juice?
Off the top of my head I will need mobo, CPU, GPU, RAM (prob go 4 gigs of Corsair or GSkill), and possibly PSU.
No. But it would be great if I could use as many spare parts as possible, like the PSU I have. In the research I did, I also decided that I am not prepared to go the i7 route either. So long story short, no particular budget but I wouldn't want to pay for more than I need.
How many 6/8 pin PCI-E supplementary power connections can your PSU provide? (For a video card upgrade)
For single video card setups, the Intel P45 chipset, specifically Gigabyte MBs, are generally seen as the "best" for Intel cpu computers for the money. (Someone with more AMD experience will have to tell you about that side of the fence.)
Definitely go with 4 GB of ram, and I would recommend DDR2 800/1066 over DDR3 due to current prices. Check for mail-in rebates.
From the Nvidia side of the fence for GPU, without a specific budget, the bare minimum for a "gaming computer" video card upgrade should be a 260 Core 216. (Someone with ATI experience fill-in for that recommendation.)
As for CPU, an Intel base computer with overclocking (and a proper CPU cooler) could have a Pentium 5x00 series as a minimum. Without overclocking, I would recommend an upgrade to a Core 2 Duo E8x00. However, you mentioned your GF using your machine occasionally for graphics work. In that case, a quad core would much better suit your needs. (I only handle duel cores atm, an Intel quad-core experienced person would need to recommend a socket LGA 775 quad-core.)
If you want to splurge on the system, upgrade to a Core i7 920 quad core. (Again, Intel camp.) However, expect to pay a VERY high premium. (As this will include the processor, high end MB, and DDR3 ram.)
If I, personally (with my non "directly researched" knowledge base), were in your shoes today, I would get the following:
Gigabyte P45 based MB
2 x 2 GB of DDR2 1066 ram (meaning it is manufacturer certified higher, thus a speed downgrade to 800 and tighter timings could be an option)
Nvidia GeForce 260 Core 216
With that setup, your current components /should/ work well.