My current configration
CPU: AMD Athlon 64 3000+ (1.8Ghz) Overclocked: 330 x 8 = 2640 Mhz
RAM: 1GB DDR 400 (3-3-3-8 @ 2T) Overclocked: 440 Mhz
Video Card: ATI Radeon x300Se
Power Supply: 450 Watts (12V - 19A)
Motherboard: ASUS A8N-E

I plan to install a new video card as the current video card sxxksbig time.
I plan to go for ATI Radeon HD3870 (PCI-E 2.0)
So all I wanna know is do i NEED to upgrade my CPU as well?
I wouldn't mind upgrading my power supply if required.

Also I would like to know (for future reference), how to figure out that a CPU upgrade is needed?

a 3000+ with a 3870 would bottleneck the GPU greatly, so yes, upgrade the cpu to avoid bottlenecking

Question: How to determine that a particular CPU would be a bottleneck?

I agree. If your motherboard supports a dual-core, I wouldn't get anything less especially with a card like that. I think you are stuck with a 939 processor so your options are limited. According to Newegg, the only Socket 939 dual-core processors available are Opterons and go for $150 a crack.

If you can manage it, you might be better off spending a few more $$ and upgrading to an AM2 board with DDR2 memory which should help keep your computer more up-to-date and upgradable for a while.

Here is what I've come up with:

Processor: 2.2GHz AM2 X2 4200+ $54 http://www.newegg.com/Product/Prod [...] 6819103214

Motherboard: Gigabyte AM2 MicroATX (lots of good reviews which we all know are 100% reliable) $80
http://www.newegg.com/Product/Prod [...] 6813128056

RAM: Crucial Ballistix Tracer DDR2-800 2x1GB (2GB) $50
http://www.newegg.com/Product/Prod [...] 6820148076

Total: $184



So either $184 for a 2.2GHz dual-core, motherboard, and 2GB DDR2-800 vs. $150 for the only 939 processor you can find online today (unless you E-Bay it).

You may also want to upgrade your PSU to something with a little more amperage (30amps or more) for better efficiency with a dual-core and that video card.

And it's hard to determine if a processor is going to be bottlenecked by mere specifications. The best way to find out is to look up existing benchmarks. But in your case, being that it's a relatively old single-core processor, it's easier to say that you will be bottlenecked. A dual-core processor is supported by many games now days and even if it isn't, the 2nd core can offload background/OS operations while the 1st core runs the game thus increasing your FPS regardless of how the code was written. The older the CPU, the more bottlenecked it will be. Yours is a couple generations behind so it will be bottlenecked by the latest video card partly due to speed (stock speed) and number of cores.

I'd say get a PGA 775 mobo, an E2160, 2gb ddr2 ram and a 3850. The cost of all that won't be far off of the cost of a 3870 and an opteron and will give way better performance

Yea if Intel was an option for OP then I'd go for that too.

Even with a decent OC, you are still on a single core. So often in new games your a little shy on the CPU end. Not a terrible match, but dual core is better for sure. I'm with Leo. S939 X2's are rare and expensive now. You would probably be better off grabbing an AM2 or S775 mobo, 2GB PC6400, and a dual core chip. Why pay twice the price for a 939 dual core than what the AM2 costs? Difference would pay for a new mobo. Also, 2Gb PC6400 costs about what another 1GB PC3200 would cost. All in all after selling the old mobo, cpu, ram you would be better off IMO. This route isn't for everyone, but for those willing and able to do it, it's worth it.

I'd get the 3870 and just see for yourself. It's not like you'll have to throw it out if the CPU starts bottlenecking it. I've got a 3800+ 939 and I can still run most of my games close to max using a 1900xtx

Go for the card. There will likely be some bottlenecking issues, but it won't prevent you from getting a nice performance boost.

Just do it, see how it goes. If anything, you buy a new CPU/Mobo after that.

Regardless, the biggest gain this fellow is going to get in one swoop is the videocard. Even with his current CPU, he's going to see a huge increase in performance with the 3870.

After than, someday, he can get a new Mobo/CPU. But since socket 939 X2s are so hard to find, I'd say the 3870 is the obvious choice.

@OP: If you get the 3870 you will need a new PSU.

Yep, just because a GPU will be bottlenecked doesn't mean it won't work. Now, if that PSU is too low, that must be remedied immediately.

yeah, of course a new GPU would help vs the X300se . I only commented on the CPU as it seems the HD3870 was a given.

But is the HD3870 the right choice for a single core CPU and 1GB RAM? If sticking to that combo, I would want to put la bit less into the GPU. A 9600GT, HD3850 or 8800GS would save money and still provide amazing gameplay for that system IMO. If dual core CPU and another gig of mem are in the works, then sure go for the 3870 or even 8800GT as it's priced so good now. (USA anyway).


And I agree, 19 amps isn't enough for the 3870 or probably any of these cards really.

+1

That card will shine. Get an Opty, and get another gig of compatible ram, plus youre skating on thin ice with that psu, depending on the make, plus the age