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The smaller 40nm design of the Radeon HD 4770 allows it to operate at 750MHz, which impressively is the same core frequency as the Radeon HD 4870. The core configuration features 640 (128x5) SPUs, along with 32 TAUs (Texture Address Units), and 16 ROPs (Rasterization Operator Units).   The memory works at a frequency of 800MHz (effectively 3.2GHz) on this particular model, and that should really make for an impressive memory bandwidth. However due to the 128-bit wide memory bus, this new graphics card is limited to a bandwidth of just 51.2GB/s, which is why it was "thought" to slot in between the Radeon HD 4670 and 4830 in terms of performance.   ASUS are shipping the Extreme AH4770 Formula with Qimonda ICs on-board (IDGV51-05A1F1C-40X parts). These GDDR5 modules are rated for 1GHz (4GHz) operation, so we suspect that given they are only operating at 800MHz, there should be quite a bit of overclocking headroom in them. Speaking of memory, according to the ATI specification the Radeon HD 4770 will only be available in 512MB flavors.  Although the Radeon HD 4770 has a thermal design power (TDP) of just 80 watts, which is just 10 watts higher than the Radeon HD 4670, it employs a dual slot cooler. This is interesting and really we expected the first 40nm graphics card to make use of a single slot cooler, especially being a mid-range contender. The dual slot cooler will provide better cooling performance and likely make less noise.  While ASUS has upgraded the cooler for better thermal performance, the dual-slot design remains. The heatsink is much larger than the standard version and does cover much of the graphics card. The heatsink features a micro surface treatment which is said to improve heat dispersion by up to 14% as this technology maximizes surface area.  Providing this heatsink with air-flow is a 75mm Y.S Tech brushless fan (YD128015ML-R), which is the same fan Thermaltake use on their DuOrb VGA cooler. Although we are not entirely sure what RPM this fan works at on the Extreme AH4770 Formula, we can tell you that when the GPU is placed under full load for an extended period of time this fan remains almost silent.   ASUS has re-worked the PCB design of the Extreme AH4770 Formula, and along the way added a few personal touches. The card now features three sets of fuse protection devices to guarantee better defense against over-current. Furthermore, with the inclusion of the EMI Shield, covered chokes, low RDS(on) MOSFETs, and solid capacitors, ASUS are aiming to make this a highly durable product.   ASUS claims that although graphics cards are equipped with controllers for over-current protection, they can fail causing the product to possibly lose performance or die altogether. Here they claim that by providing a backup over-current protection device, being “Fuse Protection”, that there will be no chance of excessive or dangerous temperature rise in the conductors. |
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