I am wanting to upgrade the Graphics Card (8400GS) and Power Supply (275w) in my HP Pavillion and trying to stay at/around, hopefully under the $200 mark before/after any rebates.

I looked at the following 2 Graphics Cards and PSU to stay at/around my $200 budget:

SAPPHIRE 100225L Radeon HD 3870 512MB 256-bit GDDR4 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail - $144.99 ($124.99 after $20.00 Mail-In Rebate) OR

SAPPHIRE 100242L Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail - $174.99 ($154.99 after $20.00 Mail-In Rebate)

APEVIA ATX-CW500WP4 500W ATX Power Supply 115/ 230 V UL, CSA, TUV, CE - Retail - $39.99 ($24.99 after $15.00 Mail-In Rebate)

Does GDDR3/4 make much of a difference?

I have a Q6600, 3GB 667 ram, 2x320GB HDDs, DVD burner, 24" monitor, Media Card reader, built in sound and wireless. Will the above listed PSU be enough to power my pc with the addition of one of the above listed Graphics Cards?

Based on the Graphics Cards listed above are they a good match to my cpu and ram as playing games on my current system is limited by my Graphics Card and not my system? I do not overclock.

Definatly the 4850!!!

I have heard great news on that card.

How about the PSU? Do I need to upgrade?

With only 16A/18A on the two 12v rails, that PSU seems a bit on the low side. The 4850s are pretty hungry, and considering that you also have a quad, you should look for a PSU with at least 30A combined on 12v. You don't want a weak PSU dying and taking your computer with it.

Edit: Definitely stay away from that PSU. As this article exposes, it only has a 350W real maximum wattage, and that with the 12v rail running as low as 11.2v - that is certainly something NOT to be desired. The 12v rail should never drop below 11.85v, nor be higher than 12.6v.

I don't understand why people are willing to spend $200 on a video card or a CPU, but only $40 on a PSU. No offense, but if there's one component that matters the most in your system, it's the PSU.

Get yourself a quality PSU. The Corsair HX520 or the Enermax Modu82+ 425W would likely suit you just fine, and both can be found on sale for less than $100. Another great feature, they're modular. Once you start working with modular PSUs, you'll wonder how you ever did without.

The vid card gives gamers more FPS (I'm definitely not willing to spend $200 on one myself not being a gamer). The faster CPU will also make most things significantly faster (especially encoding). Whereas as high-end PSU has no apparent effect. As long as it works, most people are happy, and couldn't care less what PSU they use.

Personally, I don't go for no name or very low quality PSUs, but seriously, that Corsair HX520 is $125 when not on special, that's pretty expensive for a 520W (I got a decent 750W for $74...) Yes, it's modular, but again, most people wouldn't really care. I wanted a modular PSU, but a similar PSU that's modular would have cost me like $200. As long as there's enough place for the unused cables in the case it's not a big issue (total non-issue in a big CM Stacker). It's one of those nice-to-have's, but that most people won't spend extra for. The Enermax is still fairly pricey because it's modular (~$100 for a 420W), considering you can get a half decent 450W Fortron, 400W Seasonic or 380W Antec Earthwatts around $50 (not modular though). That's like $50 extra, or double the price, for not having a few extra unused cables in your case.

Fair enough. I'm just a quiet-computer freak, and don't like having messy cables lying in my case, tucked away or otherwise.

1. DDR4 is faster than DDR3

2. I hate ATI cards always have since games are designed around the nVidia chipsets, im currently using the nVidia GeForce 8800GTS 320MB DDR3 and im only on a Core 2 Duo and so far i have not been able to max out my system with a game at all!!! Its an awsome card but power hungry needs about 24-26amps on a 12v but it has two sockets to use for power so make sure to get a decent 750watt PSU for sure.

Hope this helps

It wasn't so much that I was trying to be cheap towards the PSU, but rather get a good while being cheap PSU.

I've taken all your advice and am leaning towards the CORSAIR CMPSU-520HX 520W ATX12V v2.2 and EPS12V 2.91 Power Supply 100 - 240 V UL, CUL, CE, CB, FCC Class B, TUV, CCC, C-tick - Retail, however, to stay withing my $200 budget I am leaning towards the SAPPHIRE 100225L Radeon HD 3870 512MB 256-bit GDDR4 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail Single slot solution, Vista x64 driver support unless you can recommend a better card and still stay within my budget?

The 3870 takes a huge performance hit when using AA (anti-aliasing aka smoothing jagged lines). Even if you don't use AA you should still get the 4850.

If your budget is truly stuck at around $200, then those two would be my choices. However, if you'd like to be able to spend a little more towards your video card (to move up to the 4850), then you could always go for the Corsair VX450. Still an excellent quality PSU, and the only thing you really sacrifice is the modular cables. Before you ask - 450W will be plenty for your system (unless you're hardcore into overclocking - judging by your questions so far, you're not ).

Okay with the 4850 is my mid-tower going to be an issue as far as space is concerned?

My PC Specs - I don't know if anything from this page may be of any assistance in telling you a little more about my current pc.

The 4850 is the same length as a standard motherboard. The main concern for you is going to be if there are any connectors that run directly behind (i.e. towards the front) the PCIe x16 slot (where the 8400GS is located now).