During their GPU Technology Conference 2014 in late March, Nvidia announced a new flagship video card: the dual-GK110 based GeForce GTX Titan-Z. We had to wait a little while for its introduction, but as of May 28th this card, which comes with a price tag of close to €3000, is available for real, be it in small quantities. The folks over at Tones.be sent us their TIZAir-system, in which two of these GTX Titan-Z cards are incorporated. We tested both this system and the cards separately, using our standard test rig for video cards.
The GeForce GTX Titan-Z is based on two GK110 GPUs, the chip that we know from the GeForce GTX 780 (Ti) and the GeForce GTX Titan (Black). The board is essentially Nvidia's counterpart to AMD's Radeon R9 295X2, which in turn features two of AMD's fastest GPUs. There are a number of clear differences: where AMD chose to dissipate the heat generated by the two Hawaii chips using water cooling, the Titan-Z has been equipped with an air cooler, be it a rather gigantic one. Another difference: where AMD already had a fairly expensive card with a price of some 1500 euros, the Titan-Z's price truly is exorbitantly high: the MSRP is $2999 in America, and those across the pond would be set back around €2800 / £2670. When considering these prices, we can safely say that this card will not be offering a reasonable price/performance ratio, even without running any benchmarks.
The Titan-Z utilizes two GK110 GPUs, as was previously mentioned. For both GPUs, all 2880 shader units have been enabled, just as is the case for the GTX 780 Ti and the GTX Titan Black. We thus arrive at a total of 5760 shader units. Double-precision (64-bit) floating point GPGPU performance has not been artificially capped, just as was the case for the GTX Titan and GTX Titan Black. As a result, the card is also suitable for businesses and universities who wish to run certain scientific workloads for a relatively low price. We do have to point out that this mainly holds true for the Titan Black; the €2800 price tag of the Titan-Z makes it more expensive than all Tesla boards except the K20, which has an average price of some 3300 euros in our price comparison database. While the Titan-Z does have more memory, the difference with the 5GB K20 is only 1 GB per core. The Titan-Z is significantly cheaper than the higher-end Quadro-models, however ...
So, the GTX Titan-Z has 12 GB of GDDR5 memory on board, or 6 GB per GPU. It's common knowledge that even for SLI setups on a single card, both GPUs must have all data available in their own local memory, which means that 12 GB is only 6 GB in practice.
Based on the amount of shader units and the amount of memory, one would conclude that the GTX Titan-Z is essentially two Titan Blacks on a single card. This is not entirely true, however: the clock frequencies are clearly lower. The Titan-Z's GPUs run at a standard clock frequency of 705 MHz, with a Boost clock of 876 Mhz. In comparison, the Titan Black has a standard clock frequency of 890 MHz and a Boost clock of 980 MHz.
|Nvidia GeForce||GTX 780 Ti||GTX Titan Black||GTX Titan-Z|
|GPU clock||876 MHz||890 MHz||705 MHz|
|Boost clock||928 MHz||980 MHz||876 MHz|
|Memory||3 GB GDDR5||6 GB GDDR5||12 GB GDDR5|
|Memory clock||1.750 MHz||1.750 MHz|
|PEG connectors||1x 6-pin + 1x 8-pin||2x 8-pin|
|TDP||250 W||250 W||375 W|
While one could naturally leverage the computational power offered by the Titan-Z for scientific purposes, it obviously remains a board that is also suitable for 3D-gaming. Nvidia is clearly targeting the growing market of owners of an Ultra HD (4K) display with this card. It should be clear that a Titan-Z (just like an AMD Radeon R9 295X2 for that matter) is overkill for Full HD.
The TDP of the Titan-Z is 375 W. This is significantly less than the TDP of two separate Titan Blacks, but it is still very high. As a result, the card comes equipped with two 8-pin PEG connectors, and more importantly, with a gigantic cooler: the Titan-Z takes up no less than three slots. A single, centrally placed fan ensures that both GPUs receive sufficient airflow.
In their official presentations, Nvidia claims that the GTX Titan-Z will be just as cool and just as quiet as a single GTX Titan Black. This would be quite a feat. Naturally, we have extensively tested this as well.
Obviously, the charm of the Titan-Z is the fact that you (almost) have the computational power of two Titan Black cards on a single board. At the same time, this is the only USP: should you purchase two Titan Black cards, you'll end up saving over 1000 euros and you'll receive even slightly better performance. If you wish to combine four GPUs, two Titan-Z cards probably are a better solution than four Titan Blacks, as the cards would be directly next to each other in the latter case, which obviously isn't beneficial for their temperatures. The Tones system, which we will discuss on the next page, demonstrates that you can construct a tidy system with robust cooling using two Titan-Zs. That said, allow us to once again stress that the Titan-Z truly is a niche product, even if only because of its price tag.