Nvidia 780a Chipset Preview
Perhaps the most intriguing aspect of the board is the inclusion of what NVIDIA call mGPU (motherboard graphics processing unit). While this is hardly an innovation (on board VGA has been around for years), the 8400GS core on which the chipset version is based, is much more powerful than other on-board solutions and therefore capable of offering at the very least, low end entry in today's gaming world - I'm not for one minute saying this will run Crysis at 2560x1600 with all the trimmings but its certainly a step in the right direction if nothing else but to troubleshoot your own dedicated GPU should things go awry. This however is in retrospect as it is not what it was designed for. Hybrid SLI is the terminology NVIDIA like to use to pair two features of the 780a, Hybrid Power and Geforce Boost.
Stripping our Asus Crosshair II past its copper heatpipe we find the heart and soul of the 780a chipset, the 780a itself (above left) and the nForce200 chip (above right). I would much prefer to see an integrated heatspreader on these chips as the silicon is very easy to 'nibble' when removing the stock heatsinks should you be a little ham fisted. Intel chipsets now make use of the heatspreaders and are much more user friendly but it seems Nvidia don't consider the majority of users to rip apart a high end motherboard, fair one I guess. Luckily ours survived the process anyway so I can show you them the way NVIDIA intended (or not as the case may be).
is a power saving feature that allows the chipset to alternate processing from your main GPU to the on-board GPU which will reduce energy consumption and cut down on the noise emitted from your PC when 3D power is not required such as browsing the internet or working on a spreadsheet etc. It is more than capable of running HD content with 100% video acceleration of MPEG-2, H.264 and VC-1 codecs. Of course when you feel like a quick stint on your favourite first person shooter the chipset will automatically switch back to the dedicated GPU providing you with the power you require. At the time of writing this only two dedicated GPU's are compatible with Hybrid Power and they are the 9800GTX and 9800GX2.Geforce Boost
on the other hand works in tandem with your graphics card (if it is supported) and provides an SLI scenario providing a, erm, boost to your VGA solution. Obviously this is aimed at the low end GPU users to gain any tangeable benefit and as such a perfect match would be the 8400GS.
PureVideo HD provides high-definition video decode acceleration with post-processing to deliver HD content. It also includes HDCP capability for playing blue-ray and HD DVD movies at the highest possible quality.
Systems without PureVideo HD rely heavily on the CPU for HD codec processing which as a result can slow system responsiveness. However a system with PureVideo HD can take advantage of the on-board GPU to take on 100% of the processing of the HD codecs and in doing so the end user can continue to work as normal without the need to wait for the processing to finish before the system becomes useable once more.
With HD content rapidly becoming the norm for video playback this could be a very useful feature of the chipset in the near future.
FirstPacket Technology allows latency-sensitive applications and games to gracefully share upstream bandwidth so that your priority application, such as on-line gaming, not notice the operation of other programs despite sharing the bandwidth. The ping in games therefore will not rise to such an extent as previously encountered and will allow you to get on with what you want to do while your bandwidth hogging applications work silently in the background.
Mediashield has been around for a while now and is a common feature on previous Nvidia chipsets. That said, if you are a fan of Raid then MediaShield can now provide Raid 5 capability with up to 6 SATA drives linked into one volume. Multiple RAID arrays are also compatible with RAID 0, 1, 0+1 and 5 being supported. Perhaps the most useful feature of MediaShield is the ability to identify which drive has failed in an array which could be very time saving should you have a 6 disk array!
Nvidia 3-way/Quad SLI is the pinnacle of GPU performance with the ability to link 3 and 4 GPU's together in a 16 x 8 x 8 PCIe configuration and is perhaps the main feature which will attract potential buyers. Using a trio of 9800GTX NVIDIA claim that performance in 3D applications can be amplified by 2.8x which is a vast improvement on the scalability of previous incarnations if it is to be believed. Not only that but the awesome power of two 9800GX2's (2x2 GPU's) can be harnessed in a Quad SLI configuration to give you unparalleled gaming fluidity. Obviously you are going to need a pretty meaty PSU to power such a beast but compared to the cost of a quad SLI board along with dual G2X's, a 1kw psu is a mere drop in the ocean!
NVIDIA have also tweaked the link between the CPU and GPU to reduce the latency and optimise the bandwidth for CPU-GPU and GPU-GPU messages. This improved logic is split into two optimisations:
- Direct GPU-GPU communication (PWShort)
- Broadcast support
PWShort (Posted-Write Shortcut) is the ability of the PCIe controller to forward a message from the GPU directly to its destination. SLI configurations benefit from this as GPU's can now send a single update to all the other GPU's allowing the frame buffers to stay synchronised in effect reducing latency of the traffic and taking the stress of the memory-PCIe controller link.
Broadcast allows data to be converted from serial to parallel. Previously SLI worked by the GPU's receiving data from the CPU in serial format. The 780a chipset changes all that. The nForce 200 chip now receives the same signal from the CPU (via the 780a chip) but now splits the data and has the capability to transmit the data in parallel massively reducing congestion on the front side bus.
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