About LightRoom CC and GPU - what should I expect? What kind of GPU should I buy?

Hi Eric,

Eric Chan: Can we have an openGL test passed for our card without any benefit?

In my case, I use an AMD HD 6450 with Lr6 test passed (with previous driver from April 2014) but it's obvious that I have no benefit to use it: any zoom in the develop module with "Use GPU on" take 3-4 second instead of less than 1 second without.

Is it normal?

Thanks for all your work and help.
Alain

Hi Alain,

Unfortunately, yes it is indeed possible for the internal diagnostics to pass (the card works and renders images correctly) but for the card to not provide much practical benefit (speed) in Develop. That is, the internal diagnostics only check for correctness, not speed improvement.

The specific card that you mentioned (AMD Radeon HD 6450) is an entry-level card from early 2011. It uses an older bus interface (PCIe 2), has lower memory bandwidth (~10 GB/sec), and more limited compute resources (~200 GFLOPS 32-bit float). It is good to hear it renders correctly with the 14.4 driver, but it's unlikely to provide any speed benefit in Develop, and as you've found, will actually probably slow things down. More harm than good.

Contrast with a more recent AMD card such as the R9 270. This is from late 2013, so not the newest nor fastest card. But it supports a newer bus interface (PCIe 3 vs PCIe 2), has much higher memory bandwidth (~180 GB/sec, vs 10), and is much faster (~2300 GFLOPS 32-bit float, vs 200).

Hope this helps.

Eric