Autore: ExtremeTech

It hasn’t even been a week since AMD unveiled its new HD 7790, based on the graphics core that we’re virtually certain also powers the Xbox 720 — but Nvidia has a new card launching today that’s meant to put a serious hurt on Sunnyvale’s latest GPU. Team Green’s new GTX 650 Ti Boost is a major upgrade to the GTX 650 Ti — and given how similar the names are, that’s actually a problem.

There are now three products labeled “GTX 650.” The vanilla GTX 650 without a suffix is based on the GK107 GPU, which means you don’t want it unless you have no other choice. Current price range is $ 99 to $ 139. It’s available in 1-2GB flavors, but has just 384 cores, 32 texture units (TMUs) and 16 raster operators (ROPs). Next up, there’s GTX 650 Ti. Current price range is $ 144 – $ 180. These cards have 768 cores, 64 texture units, and 16 ROPs and come in 1-2GB configurations. Both of these cards have a 128-bit memory bus.

Nvidia GTX 650 Ti Boost

The TDP on this slide is off — Nvidia updated us at the last minute to say the card’s TDP is 134W, not 140W.

Now there’s the GTX 650 Ti Boost, with a launch price of $ 149 for 1GB cards and $ 169 for 2GB cards. It has 768 cores, 64 texture units, and 24 ROPs. It includes Nvidia’s GPU Boost technology and its maximum Boost clock is 11% higher than the GTX 650 Ti’s standard base clock. It also adds multi-GPU support (the GTX 650 Ti lacks that), and has a 192-bit memory bus. Total memory bandwidth on the Ti Boost is 1.67x higher than the GTX 650 Ti’s, thanks to a combination of higher clocks and the wider bus.

NV Performance (GTX 650 Ti vs. GTX 650 Ti Boost)

Nvidia really ought to have branded the GTX 650 Ti Boost as the GTX 655. It shares the GTX 660′s support for GPU Boost and multi-GPU configurations. Like the GTX 660, it has 24 ROPs, which puts its fillrate at 23.5 gigapixels per second — nearly double the GTX 650 Ti’s 14.8. By the time various vendors get done with their own cards, the GTX 650 family will stretch from $ 100 to $ 200 — and that’s more confusing than it needs to be.

So how’s it compare to AMD’s HD 7790?

This isn’t a particularly happy comparison for AMD. The GTX 650 Ti Boost has a substantial advantage over the HD 7790 in terms of total RAM, memory bandwidth, and peak fill rate. Performance figures at PC Magazine bear out some of the problems — while the HD 7790 is a huge upgrade over the HD 7770, the GTX 650 Ti Boost is typically 20-30% faster than the HD 7790. It also offers the multi-GPU and GPU boost options that AMD was crowing about just four days back.

AMD Radeon HD 7790

AMD does have a few advantages. The $ 20 price difference between the HD 7790 and the GTX 650 Ti Boost is pretty slim, but it does make the HD 7790 the cheaper option. AMD’s game option is arguably superior — while the GTX 650 Ti Boost comes with $ 75 in game credit for three titles (World of Tanks, Hawken, and Planetside 2), the HD 7790 comes with Bioshock Infinite. That may be enough to sway some folks, given that the game is winning rave reviews from multiple outlets.

AMD also wins on overall power consumption. Civilization V is one of a small number of titles where the HD 7790 and GTX 650 Ti Boost tie at ~58 FPS (1920×1080, DirectX 11, 4x MSAA, High Detail), but the AMD card draws dramatically less power, as shown below. Idle power consumption between the two is roughly comparable. We ran some quick comparisons between the two cards in the latest version of 3DMark and again saw the 7790 drawing far less power — in the Combined Test benchmark, the GTX 650 Ti Boost drew 185W, compared to the HD 7790′s 145W. The GTX 650 Ti Boost turned in a higher overall frame rate (7.45 FPS compared to 6.56 FPS) but if you break performance into watts per frame, AMD comes out ahead.

GTX 650 Ti Boost power consumption, vs. HD 7790

AMD’s last advantage is die size and transistor count. The HD 7790 is a 2.08B transistor GPU at 160mm2. The GK106 that powers the GTX 650 Ti Boost is 2.54B transistors and 214mm2. That means AMD likely pays less per die than Nvidia does, assuming both companies are seeing equal yields.

At the end of the day, we expect Nvidia’s performance figures will gnaw away at margins on the HD 7790 series. The $ 149 launch price for the 1GB cards may be a tough sell; don’t be surprised if AMD slots 2GB cards into that spot in the not-too-distant future. The good news is that the HD 7790 has some room to maneuver as far as manufacturing margins and is a much stronger card overall. The big winners overall are consumers, who are getting substantially better products at the same price point.