The in-house replacement for ATI's RS480 integrated northbridge/graphics core logic product has been a long time coming. Since we previewed the hardware for AMD processors back in November 2004, ATI has been absorbed by AMD, Windows Vista finally made it out of the door and the IGP game has moved on pretty significantly, be it in process technology, shader model support, video features or performance.
Ending its base evolution in RS485 form with support for Socket AM2 processors, the RS4-class of IGP products has served AMD well in both desktop and mobile spaces since its introduction, but it's become clear in the last 12-18 months that it's not the only IGP game in town, and not by a long shot in some cases. Headed up by Phil Eisler, AMD's brand new Chipset Division is responsible for today's brand new IGP product, their first following the ATI/AMD merger and long awaited by customers and press alike.
AMD 690 is the core logic family, 690G and 690V the initial family members with both implemented using the same IGP and southbridge silicon, and both supporting AMD Socket AM2 processors. Windows Vista Premium compliance is claimed no matter the variant or supporting processor and memory configuration, AMD saying that you can meet the minimum spec with 690 plus an AMD Sempron microprocessor and single-channel memory, meaning all higher performance pairings will get there too.
RS690 is the IGP northbridge component for both 690G and 690V, and packs half an RV410 pixel shader core (4 PS units with a sampler each), no vertex shader units (CPU does vertex processing in a 690 IGP system) and ATI's Avivo technology block into a 49mm² (7x7mm) die built using 80nm process technology at UMC (for comparison, RD580 was 39mm² on 110nm). RV410 as the technology donator means supports Shader Model 2.0, rather than the Shader Model 3.0 of its immediate competitors. Whether that hurts AMD in target market for 690 products is something for them to comment on, although we assume they're not too concerned about their users coming across SM3.0-only applications with no fallback path.
Supporting Socket AM2 processors with their integrated memory controller, the connected memory pool for the IGP lies in system memory at all times, with no apparent option for discrete memory module to support the IGP, using AMD HyperMemory technology. In terms of output technology the IGP can do HDMI (1.3), dual-link DVI (both that and HDMI protected by HDCP), analogue VGA and component and the usual composite and S-Video too. The entire gamut of output options, then! Most retail 690-based products are likely to sport a HDMI or DVI port, analogue VGA and then an ADD2 riser card for other possible signalling.
Avivo technology in the RS690 IGP, seen here for the first time paired with something other than R5-class GPU base technology, allows the IGP to take care of some of the heavy lifting when it comes to decoding and encoding video. The hardware decoder supports high bitrate H.264, with AMD putting their flag in the sand with a "it's best at 720p" when talking about average decoding performance over a number of video formats using typical bitrates found in broadcast and published content. Avivo is also what's responsible for the aforementioned display output technologies, including support for 10bpc output using a digital signal.
HDMI audio is provisioned by an audio controller and encryption logic in the RS690 IC, allowing it to provide protected audio over the HDMI interface and meet Vista requirements for doing so. Unprotected non-HDMI audio can still be provisioned by SB600 and a HD Audio PHY.
In terms of I/O in RS690, there's healthy PCI Express provision with 24 lanes, allowing it to be the host for a PCI Express x16 add-in card with four general purpose I/O lanes for external ICs, and the last four used for the ALINK connection to SB600.
When it comes to performance, AMD claim 690G with an Athlon X2 5200+ is measurably quicker at 1024x768 with no AA or AF, compared to NVIDIA's competing MCP61-based products, at least in a couple of games and benchmark. Our own testing of a 690G board shows that basic gaming performance (up to 1280x1024, low levels of IQ enhancement) is passable and it's more than enough to run a high-resolution Vista Aero desktop (2560x1600 no less) over the test board's DVI port.
SB600 is the 5.5x6.5mm I/O processor for 690-based products, offering 4 SATA2 ACHI ports with RAID support, a sole PATA port, 10 USB2.0 ports with good performance and 2 lanes of peripheral PCI Express. It's been around since mid to late 2006, doesn't integrate an Ethernet controller unlike competing I/O processors from other vendors, but does implement a HD Audio interface.
Comparing the two launch variants, the differences come in terms of output ability (V has no HDMI and only single link DVI) and connectivity (V won't sport a x16 PCIe slot), with 3D performance different by virtue of 350MHz IGP clock for V, 400MHz for G (but both step up from RS4-class IGPs of course). 690G products will be marketed as containing Radeon X1250 graphics, while 690V is given the lesser Radeon X1200 moniker.
Creating AMD 690-based mainboard should be a snap for any vendor that's produced an RS4xx-based board in the past, since RS690 is pin compatible with RS4xx and SB600 is of course pin compatible with SB400/450. Electrical compatibility is a given, too. Of course there'll have to be changes concerned with AM2, if the prior design was based around AMD Socket 939, but the general gist is that board designs for 690 are understood and easy to adapt.
AMD are proud of the 30+ supposed design wins for 690-based products from their mainboard partners, placing some of that count on the shoulders of the merger, where AMD is the sole point of contact for a vendor looking to implement what amounts to a full platform. Remember that CPU, graphics plus northbridge, and southbridge are all AMD products when it comes to 690. Regardless of the reason for so many board wins, the count is much healthier than it's ever been for an ATI core logic product in the past, no matter what CPU it supported, which should help them regain some lost marketshare in recent times.
It's hard not to like a Vista Premium compliant IGP-based core logic set with support for HDMI, first-rate video features and performance and support for AMD's low-power AM2 processors, at least where it concerns the media PC crowd. With a quoted power of ~8W according to AMD, and a die size of just 49mm², it's hard not to like from a mobile computing perspective either.
Your author wishes his Macbook was powered by RS690G, rather than GMA950, at least. With SB600 doing a nice supporting silicon job and board designs aplenty, we look forward to our full look at the Avivo-sporting core logic, since it seems like it's still an attractive product despite a considerable wait.
Until then, turn the page for a spot of commentary about our test AMD 690G board, the ASUS M2A-VM.