GeForce GTX 750 and 750 Ti: Meet 28 nm Maxwell
Nvidia's new graphics architecture makes its debut in a non-standard way. While their previous architectures started with flagships, the first Maxwell cards arrive as mid-range performance offerings. Both $150 GTX 750 Ti and $120 GTX 750 use the GM107 GPU, which is manufactured on 28 nm, but they have some nice tricks under their sleeve. During its 2 years in manufacturing, the 28 nm process has matured and has a more predicable performance and better yield. Nvidia managed to design GM107 with that in mind and achieved impressive improvements in power efficiency. GTX 750 Ti uses only 60W and thus can draw all the power it needs from PCI Express slots and does not require an additional 6-pin connector, unlike GTX 650. Unfortunately, Nvidia is not very enthusiastic about full DirectX 11.2 compliance, so while their cards support some tasty bits of it, the specification may not become a widely accepted standard in games anytime soon. The compute performance received a boost, partially due to the much larger cache, but FP64 performance is now limited to 1/32 of FP32 performance on GM107.
In terms of specifications, new architecture brings some changes. GTX 750 Ti has 640 CUDA cores, while GTX 750 has slightly cut down GM107 with 512 cores. Both have 1020 MHz base clock and 1085 MHz boost clock. Interestingly, benchmarking sites reports that almost all cards they have tested can be easily overclocked by additional 135 MHz before hitting the limit set by Nvidia. Cards have 128-bit memory bus, limiting their bandwidth, while using 5.4 GHz and 5 GHz GDDR5 memory. The performance of the cards makes them a minor upgrade to GTX 650 and GTX 650 Ti. Depending on the game, GTX 750 Ti can perform slightly below GTX 650 Ti Boost or outperform it and get close to GTX 660. Correspondingly GTX 750 performance varies similarly around GTX 650 Ti. As a result, they will replace these cards in Nvidia's line-up, while GTX 650 will still be sold as an even cheaper offering. The low power usage will be especially useful for people who want to upgrade on systems with weak PSU's, as GTX 750 Ti considerably outperforms all previous cards powered only via PCI-Express.
The low power consumption suggests this card as a good idea for HTPC setups. However, the time of release means that the newest standards are not supported (partially, because they are not yet complete). Thus there is no HDMI 2.0 with 4K@60Hz support or light hardware h.265 decoder. The card is still capable of decoding it, but using the general compute. The enhanced h.264 capabilities allow it to decode 4K h.264 footage easily. It will be especially nice for video tasks when passively cooled versions appear. In terms of display capabilities, both cards support G-Sync, but it depends on which version you get. Most of them come without DisplayPort required to use G-Sync.
Overall GTX 750 and GTX 750 Ti manages to excel at the performance/power ratio. However when it comes to their price things are not so simple. R9 260X has the same recommended price as GTX 750 and outperforms it. Similarly, not yet available R9 265 outperforms GTX 750 Ti for the same price. So, for people who have no problems with cards that require more power from the PSU, these new cards do not seem as a good value proposition. Still, this being the launch of a new architecture, there might be more surprises awaiting us. During the GTX 780 Ti release I did not expect 28 nm GPUs to provide more performance in such a reasonable power envelope. However, now it seems that depending on the availability on 20 nm from TSMC we may see some performance from an older process, if Maxwell in GM107 scales well to larger chips.