Reviews - Sapphire AMD (ATI) Radeon HD 4870 X2 2GB: opening up a can of whoop-ass

[miniyazz]

How much does the free upgrade actually cost you?

:-p unlike most Windows things, it's the price of a DVD and shipping (and maybe handling costs too) if you have it shipped to you, but I think unless you have a slow connection they would normally supply you with a download link, for free, which remains valid until you download it. Also, I think for Ultimate, both 32-bit and 64-bit editions are included on the disk. Your existing product key will work for both 32-bit and 64-bit editions of the same product (i.e. within Vista Premium, but not extending to Vista Home or Vista Ultimate).

And Koocha, I agree that driver incompatibilities is becoming a non-issue, but there are still programs out there that work only on 32-bit. Other than that, the only advantage of using 32-bit over 64-bit is if you have limited RAM, as a 32-bit OS and programs have a slightly smaller memory footprint than 64-bit.

[kalniel]

Might be do do with the on-card bridge - isn't the bandwidth better?

There's marginally less latency, that's all.

On-card bridge is turned OFF, for now. So, when bridge well be turned ON - probably we well see an increase in power.
It's probably turned OFF to reduce power consumption.

The sideport is off, but the on-card PCI-E 2 bridging chip is still being used.

HD4870x2 2GB = 2GB of GRAM to use = 1GB for GPU
2x HD4870 512MB in CF (all use 512MB cards in tests) = 1GB of GRAM to use = 512MB for GPU

So you got half of GRAM, and in high quality it's not enough.

Higher quality = more/larger textures = higher GRAM use/requirements

Take:
HD4870x2 2GB = 2GB of GRAM to use = 1GB for GPU
2x HD4870 1GB in CF = 2GB of GRAM to use = 1GB for GPU - the score well be probably equal or similar.

Nice theory, but it doesn't explain why 2xHD4870 512mb in CF is slower than 1xHD4870 512mb. So it's just drivers in this case.

[4zg4rt]

The sideport is off, but the on-card PCI-E 2 bridging chip is still being used.

There well be no CF without PCI-E 2 bridging chip in there.
The sideport is sort of power up tu it. So, when bridge well be turned ON - probably we well see an increase in power.

Nice theory, but it doesn't explain why 2xHD4870 512mb in CF is slower than 1xHD4870 512mb. So it's just drivers in this case.

It's only one score graph where i see, that 2xHD4870 512mb in CF is slower than 1xHD4870 512mb. I assume that the error got in when someone creat that graph.

[SiM]

It's only one score graph where i see, that 2xHD4870 512mb in CF is slower than 1xHD4870 512mb. I assume that the error got in when someone creat that graph.

Not necessarily some games don't support multi gpu well and react in this way, hence why some people prefer single fast card over 2 slower cards