AMD Radeon R9 285 Review: Feat. Sapphire R9 285 Dual-X OC
by Ryan Smith on September 10, 2014 2:00 PM ESTTotal War: Rome 2
The second strategy game in our benchmark suite, Total War: Rome 2 is the latest game in the Total War franchise. Total War games have traditionally been a mix of CPU and GPU bottlenecks, so it takes a good system on both ends of the equation to do well here. In this case the game comes with a built-in benchmark that plays out over a forested area with a large number of units, definitely stressing the GPU in particular.
For this game in particular we’ve also gone and turned down the shadows to medium. Rome’s shadows are extremely CPU intensive (as opposed to GPU intensive), so this keeps us from CPU bottlenecking nearly as easily.
With Total War: Rome 2, we’re back to a pattern of the R9 285 performing slightly better than the R9 280 it replaces. At 5% faster it’s a small difference, but it helps to secure the card’s overall lead in the averages. At this point we can only assume that we’re once again seeing color compression in action, though as an RTS with tessellation we can’t entirely rule out some of those geometry improvements playing a part too. Whatever the reason, it puts AMD in a good spot competitively. The R9 285 is once again within striking distance of the GTX 770, all the while leaving the GTX 760 behind by a rather unexpected 20%.
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mczak - Wednesday, September 10, 2014 - link
This is only partly true. AMD cards nowadays can stay at the same clocks in multimon as in single monitor mode though it's a bit more limited than GeForces. Hawaii, Tonga can keep the same low clocks (and thus idle power consumption) up to 3 monitors, as long as they all are identical (or rather more accurately probably, as long as they all use the same display timings). But if they have different timings (even if it's just 2 monitors), they will clock the memory to the max clock always (this is where nvidia kepler chips have an advantage - they will stay at low clocks even with 2, but not 3, different monitors).Actually I believe if you have 3 identical monitors, current kepler geforces won't be able to stick to the low clocks, but Hawaii and Tonga can, though unfortunately I wasn't able to find the numbers for the geforces - ht4u.net r9 285 review has the numbers for it, sorry I can't post the link as it won't get past the anandtech forum spam detector which is lame).
Solid State Brain - Thursday, September 11, 2014 - link
A twin monitor configuration where the secondary display is smaller / has a lower resolution than the primary one is a very common (and logic) usage scenario nowadays and that's what AMD should sort out first. I'm positively surprised that on newer Tonga GPUs if both displays are identical frequencies remain low (according to the review you pointed out), but I'm not going to purchase a different display (or limit my selection) to get advantage of that when there's no need to with equivalent NVidia GPUs.mczak - Thursday, September 11, 2014 - link
Fixing this is probably not quite trivial. The problem is if you reclock the memory you can't honor memory requests for display scan out for some time. So, for single monitor, what you do is reclock during vertical blank. But if you have several displays with different timings, this won't work for obvious reasons, whereas if they have identical timings, you can just run them essentially in sync, so they have their vertical blank at the same time.I don't know how nvidia does it. One possibility would be a large enough display buffer (but I think it would need to be in the order of ~100kB or so, so not quite free in terms of hw cost).
PEJUman - Thursday, September 11, 2014 - link
I used multimonitor with AMD & NVIDIA cards. I would take that 30W hit if it means working well.NVIDIA: too aggressive with low power mode, if you have video on one screen & game on the other, it will remain at the clock speed of the 1st event (if you start the video before the game loading, it will be stuck at the video clocks).
I used 780TI currently, R9 290x I had previously works better where it will always clock up...
hulu - Wednesday, September 10, 2014 - link
The conclusions section of Crysis: Warhead seems to be copy-pasted from Crysis 3. R9 285 does not in fact trail GTX 760.thepaleobiker - Wednesday, September 10, 2014 - link
@Ryan - A small typo on the last page, last line of first paragraph - "Functionally speaking it’s just an R9 285 with more features"It should be R9 280, not 285. Just wanted to call it out for you! :)
Bring on more Tonga, AMD!
FriendlyUser - Wednesday, September 10, 2014 - link
I would like to note that if memory compression is effective, it should not only improve bandwidth but also reduce the need for texture memory. Maybe 2GB with compression is closer to 3GB in practice, at least if the ~40% compression advantage is true.Obviously, there is no way to predict the future, but I think your conclusion concerning 2GB boards should take compression in account.
Spirall - Wednesday, September 10, 2014 - link
If GCN1.2 (instead of a GCN 2.0) is what AMD has to offer as the new arquitecture for their next year cards, Maxwell (based in 750Ti x 260X tests), will punch hard AMD in terms of performance per watt and production cost (not price) so their net income.shing3232 - Wednesday, September 10, 2014 - link
750ti use a better 28nm process call HPM while rest of the 200 series use HPL , that's the reason why maxwell are so efficient.Spirall - Wednesday, September 10, 2014 - link
I'm afraid this won't be enough (but hope it does). Anyway, as Nvidia is expected to launch their Maxwell 256 bits card nearby, we'll have the answer soon.