What’s the deal with AMD’s Mantle?
AMD announced a new API called Mantle at its #gpu14 conference in Honolulu. Although most of the details are still under wraps, here’s what is publicly available right now.
In the shadow of announcing the R7 and R9 series of cards, and TrueAudio at its #gpu14 conference, AMD gave the first glimpse at Mantle — an upcoming API that promises to increase performance for PC applications and ease the cross-platform development process.
AMD didn’t reveal much about Mantle, however, as it said that the full details on the API will be unveiled at its developer conference at San Jose in November.
In a nutshell, Mantle is a low-level API for AMD’s Graphics Core Next (GCN) architecture that will offer developers deep and intimate access to the hardware.
Now this is seemingly in complete contrast to the current DirectX API paradigm, which offers the exact opposite — high level access to ensure broad compatibility. After all, PCs are a smorgsaboard of hardware whereas consoles completely uniform (AMD has said “no comment” on whether the same team worked on the APUs for both consoles).
This broad compatibility does come at a performance hit, however. The tradeoff for vast compatibility is inefficiency, meaning that while a system’s GPU may be a mighty beast it isn’t being used at its full potential for the sake of compatibility. This is part of the reason why game console developers appear to do more with less; why Grand Theft Auto V looks so good on current-generation consoles despite the aging hardware they offer.
Mantle’s competitive bargain is that it will eliminate this performance penalty by giving developers “bare metal” access to GCN. AMD claims this means that this will allow developers to create new rendering techniques and up to nine times as many draw calls per second.
So that’s the first reason for Mantle. Better access to the GPU for PC developers. It isn’t intended to entirely replace DirectX, just augment it for the low-level.
Now the next reason for Mantle is to aide in the cross-platform of games between the PC and consoles. Though there are some differences between GCN 1.0 and 2.0 — mostly relating to management of memory and HSA — in theory the low level calls written for a GCN enabled PC would be wholly compatible with the APU of the Playstation 4 or Xbox One.
Now a caveat: Mantle’s success on the PlayStation 4 or Xbox One will be dependent on how much access both manufacturers give AMD to the rest of the console’s hardware. The question of low-level hardware access probably won’t be definatley answered by AMD anytime soon, even at its developer conference in November, as its skittish about talking specifics about console hardware due to NDA restrictions.
It should be noted that Mantle is not the first attempt at building a low-level API to give developers an extra edge when coding games. 3dfx, the video card king of the original Quake and Half Life era, offered developers its proprietary Glide, which promised developers the same things AMD is promising a decade and a half later. Glide was pushed from the top by the rise of DirectX and OpenGL, lack of developer enthusiasm, as well the spectacular demise of 3dfx.
AMD is promising that Mantle won’t go the way of Glide by virtue of its long list of developers it has brought on board, and the fact that every game platform will be using it. During the #gpu14 keynote, DICE’s Johan Andersson told the crowd via a pre-recorded video that his company was fully on board with Mantle and its upcoming megahit Battlefield 4 would be the first game to use the API.
While AMD’s Mantle API is promising, the question of real-world performance on PCs looms large: what will be real world performance on CPU bottlenecked systems?
The bigger elephant in the room is the fact that Mantle will only be effective on AMD systems that sport GCN. The market share of cards that have GCN is increasing, but it’s still a relatively small market share in a highly competitive market. AMD has to compete against itself with its own non-GCN APUs, Nvidia’s very prolific graphic cards, and Intel’s GPUs. Normally a company would start throwing around cash to increase the prominence of GCN and its cards, but this isn’t something that cash poor AMD — which has to resort to leasing its own premises — can do.
What was unveiled this week in Honolulu has barely scratched the surface of what Mantle is. AMD says it is unveiling many more technical details and partner announcements at its developer summit in November.