NVIDIA’s GeForce GTX 480 and GTX 470: 6 Months Late, Was It Worth the Wait?
by Ryan Smith on March 26, 2010 7:00 PM EST- Posted in
- GPUs
Odds & Ends: ECC & NVIDIA Surround Missing
One of the things we have been discussing with NVIDIA for this launch is ECC. As we just went over in our GF100 Recap, Fermi offers ECC support for its register file, L1 cache, L2 cache, and RAM. The latter is the most interesting, as under normal circumstances implementing ECC requires a wider bus and additional memory chips. The GTX 400 series will not be using ECC, but we went ahead and asked NVIDIA how ECC will work on Fermi products anyhow.
To put things in perspective, for PC DIMMs an ECC DIMM will be 9 chips per channel (9 bits per byte) hooked up to a 72bit bus instead of 8 chips on a 64bit bus. However NVIDIA doesn’t have the ability or the desire to add even more RAM channels to their products, not to mention 8 doesn’t divide cleanly in to 10/12 memory channels. So how do they implement ECC?
The short answer is that when NVIDIA wants to enable ECC they can just allocate RAM for the storage of ECC data. When ECC is enabled the available RAM will be reduced by 1/8th (to account for the 9th ECC bit) and then ECC data will be distributed among the RAM using that reserved space. This allows NVIDIA to implement ECC without the need for additional memory channels, at the cost of some RAM and some performance.
On the technical side, despite this difference in implementation NVIDIA tells us that they’re still using standard Single Error Correction / Double Error Detection (SECDED) algorithms, so data reliability is the same as in a traditional implementation. Furthermore NVIDIA tells us that the performance hit isn’t a straight-up 12.5% reduction in effective memory bandwidth, rather they have ways to minimize the performance hit. This is their “secret sauce” as they call it, and it’s something that they don’t intend to discuss at in detail at this time.
Shifting gears to the consumer side, back in January NVIDIA was showing off their Eyefinity-like solutions 3DVision Surround and NVIDIA Surround on the CES showfloor. At the time we were told that the feature would launch with what is now the GTX 400 series, but as with everything else related to Fermi, it’s late.
Neither 3DVision Surround nor NVIDIA surround are available in the drivers sampled to us for this review. NVIDIA tells us that these features will be available in their release 256 drivers due in April. There hasn’t been any guidance on when in April these drivers will be released, so at this point it’s anyone’s guess whether they’ll arrive in time for the GTX 400 series retail launch.
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palladium - Saturday, March 27, 2010 - link
clock for clock, the 920 is faster than the 860 thanks to its triple channel memory - the 860 is faster because of its aggressive turbo mode. X58 is definitely the route to go, espeacially if you're benchmarking SLI/CF setups (dual PCIe x16).randfee - Sunday, March 28, 2010 - link
go ahead and try Crysis with 3,33GHz and 4,x, minimum fps scale strangely with the CPU.palladium - Saturday, March 27, 2010 - link
shit double post, srypalladium - Saturday, March 27, 2010 - link
Clock for clock, the 920 is faster than the 860 (860 is faster because of its aggressive turbo mode). Using the P55/860 would limit cards to PCIe x8 bandwidth when benchmarking SLI/CF (unless of course you get a board with nF200 chip), which can be more significant (espeacially with high-end cards) than a OC-ing a CPU from 3.33GHz to 4GHz.Roland00 - Saturday, March 27, 2010 - link
It doesn't really add to the framerates, and having a 4ghz cpu could in theory bring stability issues.http://www.legionhardware.com/articles_pages/cpu_s...">http://www.legionhardware.com/articles_...scaling_...
B3an - Friday, March 26, 2010 - link
You're good at making yourself look stupid.A 920 will reach 4GHz easy. I've got one to 4.6GHz. And a 920 is for the superior X58 platform and will have Tri-Channel memory.
Makaveli - Friday, March 26, 2010 - link
I have to agree with that guy.Your post is silly everyone knows the X58 platform is the superior chipset in the intel line up. Secondly do you honestly think 3.33Ghz vs 4Ghz is going to make that much of a difference at those high resolutions?
randfee - Friday, March 26, 2010 - link
sorry guys but I know what I'm talking about, using Crysis for instance, I found that minimum fps scale quite nicely with CPU clock whereas the difference a quad core makes is not so big (only 2 threads in the game afaik). FarCry 2, huge improvements with higher end (=clocked) cpus. The Core i7 platform has a clear advantage, yes, but the clock counts quite a bit.As I said... no offense intended and no, not arguing against my favorite site anandtech ;). Just stating what I and others have observed. I'd just always try and minimize other possible bottlenecks.
randfee - Friday, March 26, 2010 - link
well.... why not test using the 920 @ 4.xGHz, why possibly bottleneck the System at the CPU by using "only" 3,3?No offense intended but I find it a valid question. Some games really are CPU bound, even at high settings.
Ph0b0s - Friday, March 26, 2010 - link
These new cards from ATI and Nvidia are very nice and for a new PC build it is a no brainer, to pick up one of these cards. But for those like me with decent cards from the last generation (GTX285 SLI) I don't really feel a lot of pressure to upgrade.Most current PC games are Directx 9 360 ports that last gen cards can handle quite well. Even Directx 10 games are not too slow. The real driver for these cards are Directx 11 games, the amount of which I can count on one hand and not very many upcomming.
Those that are out don't really bring much over DX10 so I don't really feel like I am missing anything yet. I think Crysis 2 may change this, but by it's release date there will probably be updated / shrunk versions of these new GPU's avaliable.
Hence why Nvidia and ATI need really ecstatic reviews to convince us to buy their new cards when there is not a lot of software that (in my opinion) really needs them.