It's been a long time coming for the budget end of Nvidia's 6-series of GPUs. Whereas AMD has had the sub-£200 and sub-£100 price points covered for most of the year now, it's only with the recent release of the GTX 660 and GTX 650 that Nvidia has been able to do the same, as the highly anticipated GTX 660 Ti failed to dip below £200 as many were expecting it to. The GTX 650 certainly has its work cut out for it; prices on AMD's cards have fallen nicely, with the HD 7750 now available for under £80 and the HD 7770 for around £90.
The lower price of GPUs in this spectrum of the market naturally means that manufacturers are able to shift higher quantities of them than high-end performance cards, and thus the need to strike a delicate balance between price and performance is essential in order to remain competitive. Though this is precisely what we saw Nvidia do with its GTX 660, our faith in the cheaper GTX 650 was shaken by the fact that Nvidia made it impossible for us to get our hands on one pre-launch. Nevertheless, we've finally managed to obtain a GTX 650 in the form of EVGA's 1GB version, which uses the stock PCB with a custom cooler. 2GB versions of the card are available, but the added memory is unlikely to make much difference in such a low power card.
Click to enlarge
Like the rest of the 6-series, the GTX 650 is still based on the 28nm Kepler architecture, but in a similar vein to the GTX 660, it features a new GPU, the GK107. This GPU is significantly cut down in comparison to even the GTX 660's GK106, as it features just a single graphics processor cluster (GPC), compared the GK106's three. This GPC is identical to those found on all other Kepler based cards, and as such is subdivided into two streaming-multiprocessors (SMXs). As each SMX contains 192 stream processors and 16 texture units, this gives the GTX 650 a total of 384 stream processors and 32 texture units, compared to the GTX 660's 960 and 80 respectively.
The single GPC/dual SMX layout of the GK106 means that it features a pair of polymorph engines (one per SMX), and therefore a pair of tessellators, as well as just a single raster engine (one per GPC). Given the reduced size of the GPU, it should come as no surprise that the transistor count of 1.3 billion is significantly smaller than the 2.54 billion of the GTX 660's GK106 GPU. Consequently, the power draw of the GK107 is equally tiny with a TDP of just 64 watts.
Click to enlarge
The core clock speed of the GTX 650 is a respectable 1058MHz, but another thing that has been cut from the budget card is Nvidia's boost technology. Without a bit of manual tinkering, therefore, the GTX 650's clock speed is limited to this level even under load.
In terms of memory, the GTX 650 features just two 64-bit memory controllers, which gives it a total of 16 ROPs as well as 256KB of shared L2 cache. With the 128-bit memory interface and 1GB of GDDR5 memory clocked at 1.25GHz (5GHz effective), the GTX 650 has a total memory bandwidth of 80GB/s, a whole 8GB/s more than its competitor from the red side, the HD 7750, although still much less than the GTX 660's 144GB/s.
Click to enlarge
The PCB layout is a pretty standard affair with the GPU sitting proudly in the middle surrounded by the four 256MB memory chips. The GPU and memory are both cooled by the dual-slot EVGA heatsink, which features a single down-draft 80mm fan. The cooler's open design means that hot air will mostly be exhausted into your case. The two GPU power phases sit without direct cooling near the front of the card along with the single memory power phase, equating to 3+1 phase power – easily enough given the small TDP.
At 152 mm in length, the card is short by today's standards, although Nvidia specifies that the GTX 650 still requires dual slot coolers and a single 6-pin PCI-E connector. The HD 7750 and HD 7770 also support Crossfire where the GTX 650 lacks SLI support. However, the GTX 650 supports triple monitor setups out of the box, something the HD 7750 cannot lay claim to.