Crossfire or better single card?

[CheesePlant]

What do you think would be best:

1 of these:

Powercolor ATI Radeon HD 4870 PCS Extreme 512MB GDDR5 TV-Out/Dual DVI/HDMI (PCI-Express) - Retail
£189.74 inc VAT

- ATI Radeon HD 4870 GPU @ 800MHz
- 512MB GDDR5 Memory @ 3800MHz
- Silent Cooling solution
- 24x custom filter anti-aliasing (CFAA) and high performance anisotropic filtering
- PCI Express 2.0 support
- ATI CrossFireX Multi-GPU Technology
- Microsoft DirectX 10.1 support
- Shader Model 4.1
- ATI Avivo HD video and display technology
- Unified Video Decoder 2 (UVD) for Blu-ray and HD Video
- Built-in HDMI with 5.1 surround sound support
- On-chip HDCP


Or TWO of these:

Powercolor ATI Radeon HD 4830 512MB GDDR3 TV-Out/Dual DVI/HDMI (PCI-Express) - Retail
£101.19 inc VAT

- ATI Radeon HD 4850 GPU @ 575MHz
- 512MB GDDR3 Memory @ 1800MHz
- 24x custom filter anti-aliasing (CFAA) and high performance anisotropic filtering
- PCI Express 2.0 support
- 256-bit GDDR3 memory interface
- ATI CrossFireX Multi-GPU Technology
- Microsoft DirectX 10.1 support
- Shader Model 4.1
- ATI Avivo HD video and display technology
- Unified Video Decoder 2 (UVD) for Blu-ray and HD Video
- Built-in HDMI with 5.1 surround sound support
- On-chip HDCP

Thanks.

 

[jak731]

in CF compatible games 2x4830, non-CF compatible games 4870

my personal choice 4870 or GTX280 for ~£10 more

no multiGPU issues to deal with

 

[CheesePlant]

Thanks.

Does the mhz of GDDR memory make much of a difference? Whats more important memory type and speed or GPU speed?