AMD’s 890GX Chipset: Low-End Price, High-End Features

The Radeon HD 4290 IGP


Perhaps the most anticipated improvements that the 890GX brings to the table are in regards to its IGP. When the 790GX first hit the streets, it was greeted by very positive reviews. Today, we hate to be the bearer of less than exciting news, but the 890GX IGP is nothing more than a higher clocked version of the one found on the 785G – hardly anything to get excited about.


Based on the same RV620 architecture, the HD4290 is nothing more than a 700MHz variant of the DX10.1 HD 4200 found in the 785G chipset. This is definitely a little disappointing, as AMD has made terrific strides in the discrete graphics arena, with numerous DX11 cards at all price points and very potent performance. It appears that we’ll have to wait for AMD’s next generation – or should we say current generation – IGP.

Aside from a higher IGP core speed, the shader count, TUs and ROPs all remain consistent at 40/4/4. There was some speculation that AMD’s next IGP would employ 80 shaders for a nice performance boost, but this is not likely until we see a chipset die shrink from the current 55nm process.

All of the new features that the 785G brought to the table remain within the 890GX, including DirectX 10.1 support, HDMI 1.3 and implementation of AMD’s UVD2. UVD2 or “Unified Video Decoder 2” brings further enhancement in the form of multiple video stream acceleration (think picture-in-picture) as well as other image quality enhancing features. Lots more information on UVD can be found here.

Like the 790GX and 785G, the 890GX also supports “Hybrid Crossfire X”, although it appears that AMD is moving away from this name in favour of “Dual Graphics”. This essentially allows the IGP core to work in tandem with a similar discrete graphics core to improve performance. There has surprisingly been a lot of confusion and contradictory information as far as which cards can be paired with the older 785G chipset, but this time AMD is calling out the HD 5400 and HD 5500 series for this purpose.

Image courtesy of AMD.

Given the 4000 series IGP name, it seems odd that a brand new DX11 card would be paired with it, but AMD claims a solid 20-25% performance boost in some titles. At this point we can only assume that pairing a non-DX11 card with a DX10.1 IGP will forfeit hardware DX11 support in whatever game is launched in this mode, but we look forward to testing out the 890X “Dual Graphics” in our lab.

We’re also pleased to see that AMD has continued to include Sideport DDR3 support for the 890GX. Sideport memory is essentially a single 64 or 128MB DDR3 IC that is dedicated for use by the IGP. Since the IGP normally has to “share” some of the main memory for its purposes, having some dedicated cache is beneficial as it is faster and can be accessed directly i.e. not having to use the CPU’s memory controller and resources to access. Board partners have produced IGP systems without Sideport memory to reduce cost, but that is more common in the lower end budget models. We’d be surprised to see any 890GX boards without Sideport memory.