Does ECC memory for a GPU require CPU support?
No. It is a property of the GPU package. Not the CPU , main RAM , nor the VRAM.
" ... So starting with the FirePro W series AMD will have full ECC support in selected models. This will include both ECC for internal SRAM caches (which is actually a free operation), and ECC for the external VRAM (accomplished through the use of a virtual ECC scheme). This functionality is going to be limited to products based on the Tahiti GPU, which means the W9000 and W8000. ... Consequently, the Pitcarin based W7000 and W5000 will have no such ECC support, mirroring their lower compute performance and emphasis on graphics. ..."
http://www.anandtech.com/show/6137/the-amd-firepro-w9000-w8000-review-part-1/6
D300 likely Pitcarin (or Curacao minor bump )
D500 likley Tahiti LE ( so present if in FirePro config. Mainstream, consumer card is hard switched off. Maybe Tahiti 2 bump. )
D700 likely Tahiti Pro ( same as above. )
It is not just the Tahiti GPU package, but the packages that are implemented as being for FirePro products for the boosted VRAM capicity and ECC feature set.
If not then Apple could definitely be adding ECC to the whole line, as it'd be a lot easier than doing it for only some cards,
If the two cards require different designs they are already in the different R&D cost zone. The VRAM sizes are substantially different so there may be two cards foundational card designs. One for D300 and then one they can scale up/down for D500/D700. The GPUs packages if Pitcairn versus Tahiti are different sizes.
I'd be surprised if did three completely custom designs. (e.g., the pictured second GPU having the PCIe SSD connector just left off, but the placement is still there. )
plus it might actually give us some justification for the cost; through and through ECC would be a pretty nifty hook for those that know why they want it
For the W7000 the justification is in part doubling the VRAM it is configured with. Apple stripped that. It appears far more likely they are just burying the "FirePro" addition in the base price and hope folks just don't look to carefully.
My worry is that if the Pitcairn in the D300's doesn't support ECC then the whole line up will be without that feature.
There is about zero good rational for doing that. Especially when they are throwing up marketing tag lines like
"... Use OpenCL to incorporate advanced numerical and data analytics features, perform cutting-edge image and media processing, and deliver accurate physics simulations. ..."
Going to be pretty tough to do accurate physics simulations that aren't game physics without ECC. Nobody serious about that is going to touch it without it. That is just a perquisite to even be in the running on the equipment checklist.
Pragmatically folks who need the higher accuracy typically also need higher FLOP "horsepower" also. Pitcairn also is a relative dog at double precision. Never mind random bit errors ... if the computational model's floats are too small you are tossing accuracy out the window at a
100% rate.
These are specs that make a difference to technical people. Unfortunately, that is not what Apple primarily uses its "Tech Specs" pages for. Those pages are far more just a different encoding of the BTO screen.
