Mobile GPU Faceoff: AMD Dynamic Switchable Graphics vs. NVIDIA Optimus Technology
by Jarred Walton on September 20, 2011 6:40 AM ESTAMD Compatibility with Recent Titles
Along with performance, we also need to discuss compatibility for the recent releases. In something of a surprise, considering the AMD driver date and the release dates of the various games, we actually managed to run all of the games without major issues on both laptops. However, application based switching didn’t always work for AMD, requiring us to use manual switching in a few instances. There was also at least one instance where manual switching had problems, requiring us to use dynamic switching. We’ll have a video and additional discussion of our concerns with the AMD UI and switchable graphics implementation on the next page, but here’s how the games stack up in terms of compatibility for both AMD and NVIDIA.
In the “works as expected” category, Duke Nukem Forever, Portal 2, and The Witcher 2 all ran without any noteworthy issues. Deus Ex: Human Revolution also ran fine, but there was no way to use application-based switching and have it run on the Intel IGP (no loss, really). The same problem occurred with DiRT 3, but with a few extra glitches. First, there was a black border on the right side of the screen—approximately 80 or so pixels wide—that shouldn’t be there; it was present regardless of resolution and even in windowed mode. Second, in manual switching mode DiRT 3 did not render properly in full screen viewing, but worked in a window. Running in a window is not a good solution, so this is a pretty serious glitch. Super Street Fighter IV: Arcade Edition on the other hand ran fine on the IGP in dynamic mode, but on the dGPU the models wouldn’t animate properly and in general the game was unplayable. The workaround is to use manual switching (which may or may not be supported on all laptops—Sony’s VAIO C supports it, and HP added the fixed function switching option in an updated BIOS for the dv6/dv7 laptops), after which the game runs properly. Also worth noting is that a few titles appear to run somewhat faster in manual switching mode, SSF4 and SC2 being two examples.
Besides the above six “new” titles, it’s important to note that all OpenGL titles are currently unsupported by dynamic switching (e.g. Enemy Territory: Quake Wars, Minecraft, presumably Rage when it launches, and as far as we know all other OpenGL apps/games). The workaround is to use fixed function (manual) switching, similar to what we had to do for Street Fighter IV—which means you’ll want to make sure your laptop supports manual switching in some form. AMD informs us that they have a working solution for OpenGL dynamic switching, but it isn’t fully tested yet. It should come out in an updated driver, hopefully before the end of this year (*cough* Rage *cough*). Then we’ll need to see Sony and HP (and anyone else using AMD switchable graphics) to release their own updated driver, and this feels like more of a question of “if” rather than “when”.
NVIDIA Compatibility and Thoughts
All of our discussions so far have centered on AMD’s Dynamic Switchable Graphics implementation and any problems we encountered. What about NVIDIA’s Optimus Technology? First, we immediately note that NVIDIA is at an advantage here, since the 280.26 WHQL drivers we used are only a month old (and there’s a new 285.27 beta driver from last week available now). While our testing is by no means fully comprehensive, so far the only issue we encountered out of the 16+ tested games is in Total War: Shogun 2. The game runs fine, but we are unable to select the Very High preset. Our best guess is that the game is querying the Intel IGP/drivers and limiting a few settings based on the detected capabilities. (We saw a similar issue in the older Empire: Total War in the past, except the last we checked it was limited to the Medium preset.) For someone with a high-end laptop (e.g. GTX 580M), the Very High settings might be desirable, but for 99% of laptops you’ll need to run at High or even Medium settings to get acceptable performance from Shogun 2. Overall, NVIDIA’s Optimus Technology is clearly the more mature and easier to use dynamic switching technology right now.
The only area I can come up with where Optimus isn’t desirable is if you want to run Linux, which isn’t high on NVIDIA’s list of priorities right now—in fact, they’ve said they’re not even going to bother trying to make Optimus work with Linux. This doesn’t make AMD’s switchable graphics solution superior in Linux, unless something has changed and the AMD drivers (or the open-source initiative for AMD GPUs) have improved since the last time we looked. I also have no idea whether AMD’s Dynamic Switchable Graphics works under Linux; it appears that AMD is doing some extra work in their drivers to make things run under Windows, so they might have the same issue as Optimus under Linux. I can’t say it really matters to me either way, as I don’t run Linux, but if you do feel free to add in your comments on which GPU vendor is better, and any information on how the switchable graphics solutions fare. My hunch is that a discrete-only NVIDIA GPU is still the way to go, and if you’re really into Linux the old-style manual switchable graphics with muxes is the better solution.
Summary of Compatibility
Our list of tested titles is obviously limited—I’m only one person, and even with a month of testing there’s only so much I can do—but so far we have yet to find a title that absolutely would not work on either the Sony or Acer laptops. For Acer (NVIDIA Optimus), nearly all games/applications worked without any extra fiddling, but you may need to manually add newer titles (or wait for NVIDIA to release a profile update). On Optimus, the only choice is to run in dynamic switching mode, but that’s generally fine because it works so well. On AMD, depending on the game you might need to select either dynamic switching or manual switching, and if you’re playing multiple games (or using some other GPU enabled application) you will very likely have to go back and forth during the course of a day of gaming. That may sound reasonable, but a lot of users want something that just works without a bunch of extra fussing around, and AMD is coming up short in that area. So, let’s go through changes and annoyances we’ve experienced in testing the Sony VAIO C, specifically as it relates to AMD’s switchable graphics.
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Death666Angel - Wednesday, September 21, 2011 - link
"but then why even have dynamic switching in the first place?"That is a good question. I myself would prefer a solution that lets me decide what to do. I wouldn't prefer dynamic switching, because I want to be in control of my hardware as much as possible. Reboot switching is of course a pain in the butt, but I see nothing wrong with a short cut manual switch for iGPU/dGPU switching. Would be preferable to me actually.
But otherwise, thanks for the article.
mars2k - Wednesday, September 21, 2011 - link
I purchased a Lenovo W520 on the first day of release. Got the Thinkpad and could never get the graphics to perform correctly. Integration with the Intel board was lousy. Lenovo's support team could do nothing. I returned the machine. I'm thinking buggy drivers were the problem.My particular problem revolved around using multiple monitors. Connecting disconnecting or configuring multi monitors would often require a reboot. Worse than worthless!
Wolfpup - Wednesday, September 21, 2011 - link
“With all my talk of switchable graphics, though, let’s make one thing clear: switchable graphics is not necessarily the Holy Grail of mobile GPUs. The true ideal in my opinion is mobile GPUs that can run fast when needed (i.e. playing games), while also being able to power off large portions of the chip and RAM and get down to IGP levels of power consumption.”THANK you for that! That's the first time I've heard that said since all this switchable graphics stuff started.
As far as I'm concerned, the GPU situation on notebooks is a disaster, and right when I thought we were finally moving in the first direction, this switchable stuff came out.
As it is now, a HUGE percent of notebooks can't use Nvidia or AMD's normal drivers. Sandy Bridge + AMD shouldn't even be on the market, and shouldn't be considered by anyone. As the article mentions-you can't use normal drivers for those, at least not today. (AMD + AMD should work sooner or later, although the A series CPUs aren't listed yet in the driver download box on AMD.com...my little c50 notebook is supported though, so hopefully the A stuff will be soon too.)
I just bought Asus' G74, which I've really liked-and one of the reasons I bought it was that it DOESN'T use switchable graphics, and it DOES use normal drivers from Nvidia. Some more expensive systems with even better GPUs can't use the normal drivers, which IMO just isn't acceptable in a $1000 purchase, let alone a $2000+ purchase.
At any rate, Nvidia's current GPUs underclock themselves to a very impressive 50mhz, several times slower even than my Geforce 9650GT from 3 years back. As mentioned, get power gating in there, and just get rid of Optimus and AMD's equivalent. Get rid of that complexity, driver/compatibility weirdness, etc.
Even once switchable graphics are gone, we're STILL not there yet...as the article mentions, most of Sony and Toshiba's notebooks can't be updated. Sager's stuff apparently can't, etc.
My Asus N80 from 3 years ago and my G74 both accept Nvidia.com driver updates just like a desktop system, no hacks, nothing weird, it just works. And that's how it should be!
Anato - Friday, September 23, 2011 - link
Shouldn't be too difficult to make GPU which can divide resources so that parts of the unit can be shut down. Even CPU's can do that and they are executing same code as compared to GPU which can be more liberal on architecture.JonnyDough - Friday, September 23, 2011 - link
"If nothing else, Sony at least knows how to tune their laptops for long battery life."Now if they can just make PS3 networking that isn't so hackable, batteries that don't explode, and Blu-Ray discs that don't cost 4X as much as an up-scalable DVD. At least they are smart enough to partner up with AMD.
pman6 - Friday, September 23, 2011 - link
AMD's solution definitely seems half assed. Their drivers are always crap....just like how they rolled out the mobile llano hybrid crossfire with crap performance.
seems like they can never get the drivers right.
I have a llano laptop with crossfire, and you would think they would be able to do split frame rendering to improve performance. but 99% of the time, crossfire game performance is worse than discrete alone.
AMD needs to get their crap together.
netkcid - Friday, September 23, 2011 - link
good job trying to switch and run dx11 apps on a dx10 igp... and then complain about it...durJarredWalton - Saturday, September 24, 2011 - link
All of the games should run on the Intel IGP; none of them are DX11 only. Double dur. The point is that they're not switching over to the IGP when the laptop is set to do so. But that's not really the major issue -- if you're running a game, you'll want it on the dGPU 99% of the time. The real issue is that the dynamic switching failed to work properly. When the competition can make it work properly, and when your non-dynamic generally can work properly, then your drivers are not finished and certainly not worthy of WHQL certification (which has apparently become a joke these days).medi01 - Sunday, September 25, 2011 - link
"Before we get to the actual meat of this review, we have a disclaimer to make: both laptops we’re comparing came to us via NVIDIA. Now, before anyone cries “foul!”, let me explain..."Let me explain: AMD not sending you whatever you want is not a good enough reason to do hidden ads for nVidia.
JarredWalton - Tuesday, September 27, 2011 - link
Thanks for speaking for AMD, but I talked to them over four times throughout the course of this review. I've had this hardware since July, if that helps you figure out how much I've been waiting for AMD to step up with something better. In effect, I told AMD when I first got the laptop, "Look guys, I've got a Sony VAIO C with Intel + AMD dynamic switchable graphics, and there are problems. There are also no recent drivers. This review won't be favorable toward your solution if you can't get me something better." If I had given them a week, or even two, sure, but two months is more than enough time to give me something better if such a thing exists.Sticking up for AMD's solution just because it's from AMD is not a reason enough to do so. The solution as it currently stands is broken. It can be fixed, but until it actually IS fixed, I cannot recommend buying it. Like I said, I'd rather have AMD discrete GPU without switchable graphics on a laptop, because then at least I can get driver updates. And if you don't need driver updates, you don't really need a discrete GPU in your laptop.