The Radeon HD 4850 & 4870: AMD Wins at $199 and $299
by Anand Lal Shimpi & Derek Wilson on June 25, 2008 12:00 AM EST- Posted in
- GPUs
Final Words
Due to circumstances quite beyond our control, this will be essentially the third time we've covered the Radeon HD 4850. AMD has managed to make the $200 price point very exciting and competitive, and the less powerful version of RV770 that is the 4850 is a great buy for the performance.
As for the new business, the Radeon HD 4870 is not only based on an efficient architecture (both in terms of performance per area and per watt), it is an excellent buy as well. Of course we have to put out the usual disclaimer of "it depends on the benchmark you care about," but in our testing we definitely saw this $300 part perform at the level of NVIDIA's $400 GT200 variant, the GTX 260. This fact clearly sets the 4870 in a performance class beyond its price.
Once again we see tremendous potential in CrossFire. When it works, it scales extremely well, but when it doesn't - the results aren't very good. You may have noticed better CrossFire scaling in Bioshock and the Witcher since our Radeon HD 4850 preview just a few days ago. The reason for the improved scaling is that AMD provided us with a new driver drop yesterday (and quietly made public) that enables CrossFire profiles for both of these games. The correlation between the timing of our review and AMD addressing poor CF scaling in those two games is supicious. If AMD is truly going to go the multi-GPU route for its high end parts, it needs to enable more consistent support for CF across the board - regardless of whether or not we feature those games in our reviews.
That being said, AMD's strategy has validity as we've seen here today. A pair of Radeon HD 4850s can come close to the performance of a GeForce GTX 280, and a pair of Radeon HD 4870s are faster across the board - not to mention that they should be $50 less than the GTX 280 and will work on motherboards with Intel-chipsets. Quite possibly more important than the fact that AMD's multi-GPU strategy has potential is the fact that it may not even be necessary for the majority of gamers - a single Radeon HD 4850 or Radeon HD 4870 is easily enough to run anything out today. We'll still need the large monolithic GPUs (or multi-GPU solutions) to help drive the industry forward, but AMD raised the bar for single-card, single-GPU performance through good design, execution and timing with its RV770. Just as NVIDIA picked the perfect time to release its 8800 GT last year, AMD picked the perfect time to release the 4800 series this year.
Like it's RV670 based predecessors, the Radeon 4850 and 4870 both implement DX10.1 support and enable GPU computing through their CAL SDK and various high level language constructs that can compile down SPMD code to run on AMD hardware. While these features are great and we encourage developers to embrace them, we aren't going to recommend cards based on features that aren't yet widely used. Did we mention there's a tessellator in there?
On the GPGPU side of things, we love the fact that both NVIDIA and AMD are sharing more information with us, but developers are going to need more hardware detail. As we mentioned in our GT200 coverage, we are still hoping that Intel jumping in the game will stir things up enough to really get us some great low level information.
We know that NVIDIA and AMD do a whole lot of things in a similar way, but that their compute arrays are vastly different in the way they handle single threads. The differences in the architecture has the effect of causing different optimization techniques to be needed for both architectures which can make writing fast code for both quite a challenge. The future is wide open in terms of how game developers and GPGPU programs tend to favor writing code and what affect that will have on the future performance of both NVIDIA and AMD hardware.
For now, the Radeon HD 4870 and 4850 are both solid values and cards we would absolutely recommend to readers looking for hardware at the $200 and $300 price points. The fact of the matter is that by NVIDIA's standards, the 4870 should be priced at $400 and the 4850 should be around $250. You can either look at it as AMD giving you a bargain or NVIDIA charging too much, either way it's healthy competition in the graphics industry once again (after far too long of a hiatus).
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0g1 - Wednesday, June 25, 2008 - link
In the article it says the GT200 doesn't need to do ILP. It only has 10 threads. Each of those threads needs ILP for each of the SP's. The problem with AMD's approach is each SP has 5 units and is aimed directly at processing x,y,z,w matrix style operations. Doing purely scalar operations on AMD's SP's would be only using 1 out of the 5 units. So, if you want to get the most out of AMD's shaders, you should be doing vector calculations.DerekWilson - Wednesday, June 25, 2008 - link
The GT200 doesn't worry with ILP at all.a single thread doesn't run width wise across all execution units. instead different threads execute the exact same single scalar op on their own unique bit of data (there is only one program counter per SM for a context). this is all TLP (thread level parallelism) and not ILP.
AMD's compiler can pack multiple scalar ops into a 5-wide VLIW operation.
on purely scalar code with many independent ops in a long program, AMD can fill all their units and get close to peak performance. explicit vector instructions are not necessary.
gigahertz20 - Wednesday, June 25, 2008 - link
http://www.hardwarecanucks.com/forum/hardware-canu...">http://www.hardwarecanucks.com/forum/ha...870-512m...The site above mounted an after market cooler on it and got awesome results. Either the Thermalright HR-03 GT is just that great of a GPU cooler, or the standard heatsink/fan on the 4870 is just that horrible. Going from 82C to 43C at load and 55C to 33C at idle, just from an after market cooler is crazy! I was hoping to see some overclocking scores after they mounted the Thermalright on it, but nope :(
Matt Campbell - Wednesday, June 25, 2008 - link
The HR-03GT really is that great. Check it out: http://www.anandtech.com/casecoolingpsus/showdoc.a...">http://www.anandtech.com/casecoolingpsus/showdoc.a...Our 8800GT went from 81 deg. C to 38 deg. C at load, 52 to 32 at idle. That's also with the quietest fan on the market at low speed. And FWIW, I played through all of The Witcher (about 60 hours) with the 8800GT passively cooled in a case with only 1 120mm fan.
-Matt
Clauzii - Wednesday, June 25, 2008 - link
I see no fan on that thing??! PASSIVE?? :O ??jeffreybt2 - Wednesday, June 25, 2008 - link
"Please note that this is with a single Zalman 92MM fan operating at 1600RPM along with Arctic Cooling MX-2 applied to the base."magnusr - Wednesday, June 25, 2008 - link
Does the audio part of the card support PAP? If not all blu-ray audio will be downsampled to 16/48...NullSubroutine - Wednesday, June 25, 2008 - link
I would just like to point out that the 4870 falls behind the 3870 X2 in Oblivion while in every other game it runs circles around it. To me it appears to be a driver problem with Oblivion rather than an indication of the hardware not doing well there. Unless of course the answer lies in the ring bus of the R680?orionmgomg - Wednesday, June 25, 2008 - link
I would love to see more benchmarks with the CPU OCed to at least 4.0All the CPUs you use can hit it NP.
Also, what about at least 2 GTX 280 Cards and their numbers. Noticed that you did have them in SLI cause the power comsumption comparisons had them, but you held back the performance numbers...
Lets see the top 4 cards from ATI and Nvidia compete in dule GPU (no punt intended)on an X48 with DDR3 1600 and a FSB of 400x10!
That would be really nice for the people hoe have performance systems, but may still be rocking out a pair of EVGA 8800Ultras, cause their waiting for real numbers and performance to come out - and their still paying off theye systems lol... :]
Ilmarin - Wednesday, June 25, 2008 - link
You're probably aware of these already, but I'll mention them just in case:* Page 10 (AA comparison) is malformed with no images
* Page 21 (Power, Heat and Noise) is missing the Heat and Noise stuff.
Heat is a big issue with these 4800 cards and their reference coolers, so it would be good to see it covered in detail. My 7800 GTX used to artifact and cause crashes when it hit 79 degrees, before I replaced it with an aftermarket cooler. Apparently the 4870 hits well over 90 degrees at load, and the 4850 isn't much better. Decent aftermarket coolers (HR-03 GT, DuOrb) aren't cheap... and if that's what it takes to prevent heat problems on these cards, some people might consider buying a slower card (like a 9800 GTX+) just because it has better cooling.
Anand, you guys should do a meltdown test... pit the 9800 GTX+ against the 4850, and the 4870 against the GTX 260, all with reference coolers, in a standard air-cooled system at a typical ambient temp. Forget timedemos/benchmarks... play an intensive game like Crysis for an hour or two, and see if you encounter glitches and crashes. If the 4800 cards can somehow remain artifact/crash free at those high temps, then I'd more seriously consider buying one. Heat damage over time may also be a concern, but is hard to test for.
Sure, DAAMIT's partners will eventually put non-reference coolers on some cards, but history tells us that the majority of the market in the first few months will be stock-cooled cards, so this has got be of concern to consumers... especially early adopters.