GPU vs MoBo FSB speed

[ThomasKaira]

Simple question: What value on a GPU would I want to compare to my Motherboard's Front Side Bus speed to determine ideal performance? Would it just be the core clock speed?

[_echo]

Neither as the GPU will not be running directly on the FSB, but rather on the PCI-e bus. Check what version of PCI-e your car uses and your motherboard provides (IE PCI-e 1.0, 2.0, or 3.0) All of which are backwards compatible but matching versions will provide the most optimal performance you can get on the bus.

[ThomasKaira]

The card in question is PCI-E 2.0 x16, which I have several of those slots on my MoBo.

So, all I really need to be concerned about is the PCI-E bus speed. Does that tend to be variable or is it usually a reliable value?

(I'm trying to figure out if any bottlenecking might occur on my current MoBo for a GPU upgrade, and if so, exactly where it would occur).

Specs:

Motherboard: MSI P6N Diamond PCI-E

Firmware: nVidia nForce 680i

OS: Microsoft Windows XP Pro SP3

Memory: 3GB DDR2 RAM @800MHz

Processor: Intel Core 2 Quad Q6600 @ 2.40 gHz

Graphics: nVidia GeForce 8800GT

>512MB GDDR3 VRAM @900MHz

>Shader Model 3.0

Audio: Creative SB X-FI Titanium

>Turtle Beach EarForce X41 Digital Surround headset

Card in question is the nVidia GTX 460. I'm pretty confident, but I'm trying to convince a couple others that this is a worthy investment (the GPU is intended as a Birthday gift).

Edited June 16, 2011 by ThomasKaira

[_echo]

The PCI bus has to communicate with the Northbridge before it can head on to the FSB. The PCI bus is a set speed. Period. (Depending on version - Wiki)

On that system, the bottleneck is your hard drive. Everything else is fairly efficient. With a 460 slapped in there, the bottleneck becomes the graphics card demanding more information then there is, so it starts to idle, which isn't necessarily a problem.

Another potential limiting factor is only having 3GB of ram, but again, minor.

Really, whoever you are trying to convince... no offence, honest... doesn't know much. The performance boost you will see from an 8800 to a 460 will be astounding. (the difference between 112 cores vs 336... just dont get the SE version)

[Meo]

There will be a bottleneck for sure, the cpu will be to blame, BUT you will see improvements in games, especially DX10 and 11 games. So you can forget SLI, you're cpu wouldnt be able to keep up at all.

DO NOT upgrade your cpu either. Why? Cause to see any improvement you would need to get a Q9550 at least... might as well save up for a i7 2600, they're the same price.