The emergence of a new GPU architecture does not only make records in the performance of high-end graphics cards, but often changes the idea of what to expect from an inexpensive card with a low TDP. Let see what can offer GT 640 — associate member of the family Kepler
The lower segment of the GeForce 600 is already fully staffed. In retail, there are cards GT 610, GT 620, GT 630 and GT 640, and in the OEM- channels additionally supplied GeForce 605. But among all of them, only GT 640 can be called a fully new model, since it is based on the architecture of Kepler, and the remaining cards are a familiar model series GeForce 400 and GeForce 500 Architecture (Fermi) with certain minor modifications.
GeForce 640 is based on the GK107 chip, which previously debuted in accelerators GeForce 640M. The performance of the last was comprehensively studied on the laptop Acer Aspire M3-581TG: compared to the GeForce 540M new chip provides a very nice speed boost. GK107 contains one quarter of the computational units of flagship processor GK104: two streaming multiprocessor (SMX), enclosed in a Graphics Processing Cluster (384 core CUDA). Of the four memory controllers there are only have two, which gives the width of the bus 128 bits, out of the 32 ROP only 16 left, out of the 128 texture units — 32 pcs. GK104 supports PCI-E 3.0 bus.
GK107 in the desktop GeForce GT 640 is deprived of the restrictions on energy consumption and therefore operating at a fairly high frequency of 900 MHz. GPU Boost Technology in the GT 640 is not used, so the frequency is fixed.
Thus, by itself GK107 is a serious player in its class, but the GeForce GT 640 card for retail sale in a form as it is conceived NVIDIA, does not allow it to unleash the full potential. The official specification GT 640 provides for the use of GDDR3 memory with an effective frequency of 1782 MHz, the bandwidth is not enough even for the previous NVIDIA cards in this segment.
Power consumption of GT 640 is placed in a package of 65 watts. At rest, card consumes 15 watts. This is somewhat larger than the Radeon HD 7750, which has a TDP of 55 W and at rest consumes less than 3 W at the expense of technology ZeroCore.
The cooler is designed so that when installing the motherboard it is placed in the groove, cut in the edges, and the radiator embraces it with the two sides. It uses a copper base and three heatpipes. Memory chips do without additional cooling. In its implementation of the ZOTAC GeForce GT 640 uses not a full-size port HDMI, but its mini version.
Printed circuit board is compact and simple. The power supply system provides only two phases. Memory chips are located only on the front side. GT 640 does not have the means to measure and adjust the software supply voltage GPU, in addition, the card has a weak power system, and passive cooling. But, despite all the contradictions, it was essentially overclocked: from the standard 900/1782 to 1062/2242 MHz for the GPU and memory respectively.
Meanwhile, even the youngest scion of the family Kepler could expect more than a victory over the old model with obviously less powerful GPU. However, in most tests GT 640 has not reached the level of the GeForce GTS 450, not to mention the GTX 550 Ti. More modest achievements of GT 640 compared to Radeon HD 7750, because the cards are in the same range of energy consumption and the HD 7750 has technically even lower TDP.
To blame for everything, of course, is slower memory GDDR3. It severely limits the potential of the kernel GK107, pretty good for its category staffed computing units. GT 640 in its present form simply has no use if for the same money a Radeon HD 7750 can be bought. Wait for the version with GDDR5 and give it a second chance.
As for the “passive” GeForce GT 640 in the implementation of ZOTAC, there are no special claims. On the one hand, silent passive cooling can only be welcomed, on the other — the processor is overheating badly on the open bench, which, in other matters, is not surprising. However, a small active cooler, perhaps, not too noisy could cool significantly the GPU. The problem with the temperature can be solved through hinged fan, but then it will have another expansion slot.
640 GT ZONE Edition would be a good choice for a quiet HTPC, but there is an ambush in the form of a mini-version of the HDMI port and the need to separately buy an adapter or cable to connect to a TV with a full-size connector.