Scott Michaud writes: While DirectX 12, Mantle, and Vulkan allow developers to list all GPUs in a system, and communicate with them individually, Crossfire and SLI accomplished that task in DirectX 11 and OpenGL. Apart from the very early implementations, which interleaved monitor scanlines (or otherwise cut up a single frame) between devices, these systems used the Alternate Frame Rendering (AFR) algorithm to divide work. Because neighbouring frames require roughly the same amount of work, and old APIs submit work through restrictive interfaces, memory was mirrored across GPUs and, except for AMD's Hybrid Crossfire and LucidLogix HYDRA Engine, GPUs needed to be roughly identical. The new APIs open the dialogue between software and hardware, but the load balancing algorithms, themselves, have their own limitations.
StartsWithABang writes: The Big Bang takes us back to very early times, but not the earliest. It tells us the Universe was in a hot, dense state, where even the possibility of forming neutral atoms was impossible due to the incredible energies of the Universe at that time. The patterns of fluctuations that are left over from that time give us insight into the primordial density fluctuations that our Universe was born with. But there’s an additional signature encoded in this radiation, one that’s much more difficult to extract: polarization. While most of the polarization signal that’s present will be due to the density fluctuations themselves, there’s a way to extract even more information about an even earlier phenomenon: gravitational waves that were present from the epoch of cosmic inflation! Here's the physics on how that works, and how we'll find whether BICEP2 was right or not.
Lasrick writes: What a great idea. The Old Weather Project uses old logbooks to study the weather patterns of long ago, providing a trove of archival data to scientists who are trying to fill in the details of our knowledge about the atmosphere and the changing climate. 'Pity the poor navigator who fell asleep on watch and failed to update his ship’s logbook every four hours with details about its geographic position, time, date, wind direction, barometric readings, temperatures, ocean currents, and weather conditions.' As Clive Wilkinson of the UK's National Maritime Museum adds, 'Anything you read in a logbook, you can be sure that it is a true and faithful account.'
The Old Weather Project uses citizen scientists to transcribe and digitize observations that were scrupulously recorded on a clockwork-like basis, and it is one of several that climate scientists are using to create 'a three-dimensional computer simulation that will provide a continuous, century-and-a-half-long profile of the entire planet’s climate over time'--the 20th Century Reanalysis Project. Data is checked and rechecked by 3 different people before entry into the database, and the logbook measurements are especially valuable because it was compiled at sea. Great story.
samzenpus writes: Warren Ellis is an acclaimed British author of comics, novels, and television who is well known for his sociocultural commentary. The movies Red, and Iron Man 3 are based on his graphic novels. In addition to numerous other comic titles he started a personal favorite, Transmetropolitan. Ellis has written for Vice, Wired UK and Reuters on technological and cultural matters, and is co-writing a video project called Wastelanders with Joss Whedon. Warren has agreed to give us some of his time to answer any questions you may have. As usual, ask as many as you'd like, but please, one per post.
Vigile writes: Today Intel released its updated E-class, enthusiast platform based on Haswell, known previously as just Haswell-E. The Core i7-5960X Extreme Edition CPU is an 8-core processor (addressing 16 threads with HyperThreading) that doubles core count over mainstream Haswell parts and jumps from the 6-core parts in previous E-class platforms. That not only turns into dramatic performance increases in highly threaded applications like rendering and encoding, but Haswell-E is also the first consumer platform to integrate a quad-channel DDR4 memory controller, with frequencies starting at 2133 MHz. The top two tiers of Haswell-E processors also include 40 lanes of PCI Express 3.0 while the lower cost Core i7-5820K will be limited to 6-cores and 28 lanes of PCIe. New motherboards based on the new X99 chipset are required as well and include additional storage options like 14 USB ports and 10 SATA 6.0 Gbps channels. Clearly this is the fastest consumer platform tested but as with all E-class releases, the cost is higher. The Core i7-5960X will set you back $999 and expect to pay at least $500 for a motherboard and 4 DIMMs of the new DDR4 as well.
Phopojijo writes: Guennadi Riguer, chief architect of Mantle at AMD, answered a few questions about the technical details of their new graphics API. Of particular note, he discussed the potential for game developers to load balance across mismatched Mantle-supporting GPUs (for example, if an end user purchased a new video card and installed it alongside their old one). He also discussed how the graphics pipeline is evolving and the possibility of fixed-function hardware doing the same.
Phopojijo writes: The recently released AMD Radeon R9 290X has an advertised shader clock rate of "up to 1GHz". The card brought formerly $1000-level performance down to a $550 price point. Its benchmarks tend to fluctuate wildly, however, based on the card's ability to maintain an intended maximum temperature of 95C. By analyzing across a variety of fan speeds, AMD's default settings are characteristic of a 727 MHz base clock with an average boost to 850-880 MHz. At these defaults, the card will not maintain 1GHz for more than a couple of minutes (or less).
An anonymous reader writes: On the whole, Battlefield 4 had a reasonable launch. The have clearly learned from their past experiences with Battlefield 3 and, more notably, SimCity. Still, some customers are unable to access the game (until presumably October 30th at 7PM EDT, 39 hours after launch) because they are incorrectly flagged by region-locking. Do regional release dates help diminish all the work EA has been putting into Origin with their refund policy and live technical support? Should they just take our money and deliver the service before we change our minds?
Vigile writes: AMD is releasing its fastest single GPU graphics card today, the $549 R9 290X based on a new, 6.2 billion transistor GPU called Hawaii. The brand new part has 2,816 stream processors and has a peak theoretical performance of 5.6 TFLOPS. PC Perspective has done a full round of testing on the card to see where it stacks up and it does in fact beat the GeForce GTX 780, a card that costs $100 more. In fact, it also compares well to the $999 GTX TITAN flagship. Maybe more interesting is the completely redesigned CrossFire integration that no longer uses a bridge and fixes the CrossFire + Eyefinity/4K pacing issues that have plagued AMD for some time. As it turns out, with this new hardware, 4K tiled display CrossFire appears to be corrected.
JoshMST writes: So why are we in the middle of GPU-renaming hell? AMD may be releasing a new 28 nm Hawaii chip in the next few days, it is still based on the same 28 nm process that the original HD 7970 debuted on nearly two years ago. Quick and easy (relative terms) process node transitions look to be a thing of the past with 20 nm lines applicable to large ASICs not being opened until mid-2014. This covers the issues that we have seen, that are present, and that which will be showing up in the years to come. It is amazing how far that industry has come in the past 18 years, but the challenges ahead are greater than ever.
Vigile writes: While 4K displays have been popping up all over the place recently with noticeably lower prices, one thing that kind of limits them all is a 30 Hz refresh rate panel. Sony is selling 4K consumer HDTVs for $5000 and new-comer SEIKI has a 50-in model going for under $1000 but they all share that trait — HDMI 1.4 supporting 3840x2160 at 30 Hz. The new ASUS PQ321Q monitor is a 31.5-in 4K display built on the same platform as the Sharp PN-K321 and utilizes a DisplayPort 1.2 connection capable of MST (multi-stream transport). This allows the screen to include two display heads internally, showing up as two independent monitors to some PCs that can then be merged into a single panel via AMD Eyefinity or NVIDIA Surround. Thus, with dual 1920x2160 60 Hz signals, the PQ321Q can offer 3840x2160 at 60 Hz for a much better viewing experience. PC Perspective got one of the monitors in for testing and review and found that the while there were some hurdles during initial setup (especially with NVIDIA hardware), the advantage of a higher refresh rate made the 4K resolution that much better.