Nvidia GeForce GTX 660 2GB Review

Written by Harry Butler

September 13, 2012 | 13:58

Tags: #650 #660 #gtx-660-review

Companies: #nvidia

Nvidia GeForce GTX 650 1GB Preview

Manufacturer: Nvidia
UK Price (as reviewed): MSRP £90 (inc VAT)
US Price (as reviewed): MSRP $109 (ex TAX)

GTX 650 – The card you (probably) haven’t been waiting for

Alongside the GTX 660 2GB, Nvidia is also launching the GTX 650 1GB today. However, while the GTX 660 looks to be a highly competitive card at £180, the GTX 650 is much, much cheaper with an MSRP of just £90, seeing it face off against AMD’s HD 7750 1GB. With a £90 price gap between two, we doubt we’ve seen the last from Nvidia for this generation just yet.

As with the GTX 660 2GB, the GTX 650 1GB also uses an entirely new GPU design, dubbed GK107. As with the GTX 660 2GB’s GK106, at its core GK107 is still based on the Kepler architecture, with GPCs subdivided into a pair of SMXs. However, for theGK107 there’s just a single GPC, with a pair of SMX’s inside. This means a total stream processor count of 384 ( 2 x 192 ) and a total of 32 texture units (2 x 16) but also means that, while there’s a pair of polymorph engines (and as such, tessellators), there’s only one raster engine for the whole GPU, in comparison to the three on-board the GTX 660 2GB.

Also cut from the GTX 650 is Nvidia’s GPU boost technology. While the card retains a unified shader and core clock speed, it’s locked at 1,058MHz. As it’s such a stripped down version of the architecture, there have also been reductions when it comes to the card’s memory interface. A pair of 64-bit memory controllers means a 128-bit memory interface, and with its 1GB of GDDR5 running at 1.25GHz (5GHz effective), this means a total memory bandwidth of 80GB/sec. In this regard then, Nvidia has an edge over AMD, as its HD 7750 1GB boasts just 72GB/sec. The pair of memory controllers also means just 16 ROPs (eight per controller) and 256KB of L2 cache.

Nvidia GeForce GTX 660 2GB Review Nvidia GeForce GTX 650 1GB Preview
We're still waiting on a GTX 650 1GB sample; for now we've just got the block diagram to go on

As it’s cut-down to such a degree (just a quarter of the stream processors of the GTX 680 2GB), the GK107 GPU uses only 1.3 billion transistors. The reduced transistor count means a substantially reduced TDP of just 64 watts, although oddly Nvidia specifies that the card still requires a 6-pin PCI-E power connector and a full-height dual slot cooler. In comparison, the HD 7750 1GB requires no power connector and is widely available as a single slot card. Nvidia has also indicated that the GTX 650 will be available in 1GB and 2GB variants, although it’s unlikely that adding an extra 1GB of GDDR5 to such a low-power GPU will make too much difference to performance.

While we can paw over its technical specifications though, we’ll have to wait until next week before getting the chance to put a GTX 650 1GB through its paces, but with an MSRP of just £90, you shouldn’t expect earth-shattering performance.
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