AMD’s 740G: From Obscurity To Your Desktop
We’re glad that someone at AMD let us know about the 740G chipset ; else it likely would have slipped under the radar. Not that we would have been missing something new—740G is really one part 690G and one part SB700, yielding a mixed platform centering on old technology, but still able to serve up a respectable list of features. The bright side is that 740G-based motherboards are priced anywhere from $55 to $65 dollars.
The 740G Northbridge
AMD’s 740G connects to a Socket AM2 interface by means of its HyperTransport 1.0 interface. If you were planning on building a budget box using an Athlon X2 anyway, the step back from HyperTransport 3.0 won’t affect performance at all. But if you instead use a Phenom X3 or X4, the chipset will force those CPUs to run at a 1 GHz interface speed.
Naturally, because memory support is determined by the processor you choose (and its integrated memory controller), the 740G shouldn’t affect you there. However, it is worth noting that the integrated graphics core—unaided by onboard side-port memory—relies on memory bandwidth performance for gaming. If you drop in an Athlon X2, as we have for our most value-oriented configuration, you’ll top out at 800 MHz DDR2 memory. Swap in a Phenom X4 9850 for comparison and you’ll have the bandwidth of 1066 MHz modules at your disposal instead.
Can the graphics core even do anything with that extra memory throughput ? After all, the 740G is derived from AMD’s 690G, which takes its design cues from the old ATI Radeon X700. It includes four pixel pipelines that satisfy Microsoft’s DirectX 9 SM 2.0b specification—a far cry from the Shader Model 4.0 parts we’ve spent so much time playing with lately. The core runs at 400 MHz, and the BIOS included with our Gigabyte MA74GM-S2 allows manual overclocking of the GPU, though the 80nm part isn’t likely to be as flexible as the 55nm 780G. A pair of independent display outputs (VGA and DVI in the case of our sample) sets the stage for as many as four monitor outputs if you add an inexpensive discrete board.
Remember, this is older technology. So while AMD does include its Avivo video processing engine, it isn’t the Avivo HD block introduced with AMD’s DirectX 10 parts. You do get scaling support, decode acceleration for MPEG-2, and 3:2 pulldown detection. Not part of the package is acceleration of Blu-ray content—a handicap that you’ll see manifest itself in our benchmarks.
The SB700 Southbridge
All there is to know about AMD’s SB700 southbridge is already known. And it’s hardly exciting after the announcement of SB750 alongside the 790GX platform. Nevertheless SB700 is at least a step up from the SB600 component that accompanied 690G. With SB700, you get six SATA 3 Gb/s ports with RAID 0, 1, and 10 support (RAID 5 surfaced with SB750). The I/O controller also enables 14 USB ports, 12 of which are of the USB 2.0 variety. And of course, the southbridge has the same troubles with AHCI as AMD’s other storage components. We tried to get Vista installed with AHCI enabled, just to be sure, and the setup hung before completing.
More important than the chipset itself is the platform we’re building with it. Truly a product of penny-pinching in the name of science, we actually put together quite the collection of go-fast hardware.
|Processor||AMD Athlon X2 4850e @ 2.5 GHz|
|Memory||4 GB (2 x 2 GB) Corsair Dominator DDR2-1066 5-5-5|
|Graphics||Radeon 2100 Integrated|
|Hard Drive||Seagate Barracuda 7200.11 500 GB SATA 3 Gb/s|
Total cost for the platform, sans optical drive (grab a dual-layer DVD burner for $35) and chassis (InWin’s BK623 with a 300W power supply runs $60) is about $360. With those other components, you’re looking at a $450 machine. Spend an extra $50 on graphics, and the platform becomes even more capable.
The benefits of this setup are clearly upfront cost- and energy-related. Though the CPU runs at 2.5 GHz and sports two cores (each with 512 KB of L2), it’s a 45 W part sitting on a microATX motherboard with integrated graphics. In fact, you could probably shave $75 off the price by stepping back to 2GB of DDR2-800 (we used Corsair’s Dominator modules for the sake of drawing an even comparison to the other benchmarked configurations).