AMD 780G demystified - 02
AMD SB700 southbridge
HEXUS' one major lament about previous ATI chipsets has centred on the lacklustre performance of their southbridges. Where Intel set the industry standard with its ICHx series and NVIDIA piled on the features (although not all of them working) with its MCPs, ATI, now part of the greater AMD, had struggled to match either in specifications or performance.In particular, USB performance had been, well, dire, and SB600 had run its course well before RD570 was introduced. We had expected the major update, SB700, to ship with the Spider-forming, non-IGP 7-series chipsets in November 2007, but it's here now.
SB700 adds to the incumbent's feature-set by having six SATAII ports, of which two can be reserved for eSATA usage. Further, the USB count is boosted to 14, comprising of 12 USB 2.0 and two USB 1.1, and AMD promises greater performance, too. Again, we'll put this to the test.
Helping to configure esoteric RAID arrays, AMD is introducing RAIDExpert, an easy-to-use, OS-based GUI that we saw demonstrated at the press conference.
RAID is now available in 0, 1, 10 flavours, but RAID5 support is conspicuous by its absence, and AMD's representatives were keen to point out that it will be rolled into the upcoming SB750.
Also missing when compared to its rivals' recent efforts, networking support will be implemented externally via an all-in-one PHY and MAC.
There is single PATA channel support for up to two drives and, now, HyperFlash support - where non-volatile NAND memory is placed between system and hard-drive to speed-up system performance via Windows ReadyBoost and ReadyDrive protocols. Note, however, that the HyperFlash module, if specified, will connect via an IDE (PATA) interface, removing PATA drive access altogether.
Whilst the SB700 is bereft of PCIe laneage, which is all run off the northbridge, conventional PCI support is still provided, of course.
In summary, the SB700 is still a little light on features but, should performance be adequate, makes for a decent bedfellow for the 780G northbridge.
Other considerations
We've explained the beating heart of the 780G chipset, comprising of the 780G northbridge and SB700 southbridge, and we expect the majority of AMD's board partners to produce their own designs, ready to ship not much after you finish reading these wordsThe majority of boards will ship in a mATX form-factor with passive cooling on both bridges, and we expect to see basic, no-frills boards e-tail from around £60.
ASUS is one manufacturer that will produce full-ATX-sized boards from the get-go, opening the possibility of better cooling and more-extravagant tweaking.
AMD is set to concurrently launch a lower-specified variant, 780V (RS780C). The DX10 IGP remains the same, dubbed Radeon 3100, but is clocked in at 350MHz rather than the 500MHz for the G-variant. Further, there's no integrated UVD, DisplayPort, SurroundView or Hybrid CrossFire support, either. We expect to see retail models from £40 upwards.
Looking across platforms, AMD will also release a mobile-oriented version that's designed with the Griffin/Puma platform in mind, and some of the power-saving features inherent in the desktop 780G design liberally borrow from 780M.
Pre-benchmark summary
With the rather large proviso that we're basing our summary on paper specifications, AMD's 780G expands on the 690G's feature-set in a number of ways. The most compelling enhancements centre around the integrated Radeon HD 3200 graphics, which provide DX10-class compliance needed to run all the latest games.Please, please note that whilst it is, on paper, comfortably faster and more feature-rich than any IGP that has gone before it, a £50 discrete card will run frame-rate rings around it - it's designed as a graphics core for the casual gamer who wants to play new-ish games at 1,024x768 with low-to-medium image-quality settings. It should, however, provide perfect rendering without blemishes common to Intel's G-series IGPs. AMD 780G, too, can be coupled with a discrete Radeon HD 3400 card for Hybrid CrossFire.
Native display outputs are better than the competition's - be it NVIDIA or Intel's, and we can see a mATX-sized 780G board coupled with a low-power, dual-core Athlon 64 CPU as eminently sensible choices for an HTPC.
The bad? We guess it's the continuing fight against competitors whose marketing budgets are larger. AMD really, really needs to have the 780G in £399/$599 system-integrator boxes from all and sundry.
Let's see if 780G can fulfill its on-paper potential as we take a look at Gigabyte's GA-MA78M-S2H and further evaluate the Hybrid CrossFire and high-definition video-decode propositions.