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No 7.1 LPCM audio for AMD 785G boards

Published on 6th August 2009 by Richard Swinburne

AMD 785G: No 7.1 audio here folks.

In our AMD 785G launch coverage we wrongly assumed that because AMD had upgraded its HDMI bandwidth to "1.3", its UVD core to "2.0" and its IGP to "Radeon HD 4200", that this was directly comparable to the "2.0" version numbering used on the desktop Radeon HD 4xxx series of graphics cards. Unfortunately, this doesn't seem to have been the case, as AMD confirmed with us this afternoon that the audio block on its 785G northbridge has not changed since the 780G - it still only supports DVD quality, 5.1 channel audio at most: S/PDIF throughput, basically.

It does not allow 7.1 channel LPCM audio that we had previously stated. This multichannel HD audio is key for HTPC enthusiasts with prosumer audio equipment. Admittedly, this is a relatively small number of people, however it's a feature both Intel and Nvidia which have supported on their chipsets since last year.

Since the launch, Anandtech has discovered that since retail drivers and products have launched, this multichannel HD audio support has either gone missing or was never included in the first place.

Unfortunately due to lab limitations on our part, we couldn't check this for ourselves, so we took AMD's hints at a complete feature for granted. In hindsight we should have asked specifically, rather than assumed the full UVD was ported from the desktop products.

However, it has to be said that it's not the first time AMD has shipped products with sneaky differences. The Radeon HD 4890 for example was shipped to us with different clock speeds than was advised in the documentation provided, and then there's the Radeon HD 4770, where the reviewers' sample was almost a completely different product to what end users ended up being able to buy. While we will endeavor to be more vigilant in future with the detail, it doesn't bode well for AMD to act this way - not just for the reviewer:manufacturer relationship, but also for readers who want clear and accurate coverage of products they're considering buying.

We have amended the articles accordingly to represent the correct information: a guide to the AMD 785G chipset, and a review of Gigabyte's GA-MA785GMT-UD2H motherboard.

Discuss in the forums.

10 Comments

Discuss in the forums Reply

l3v1ck 6th August 2009, 11:43

There's been a lot of confusion about this issue. There have been plenty of other websites (eg Anandtech) that initially reported that this chipset would have 7.1 LPCM audio. A very poor bit of PR from AMD here.

wiak 6th August 2009, 12:52

i heard that 785G boards with ALC889A audio codec from realtek will support LPCM 7.1
http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=28&Level=5&Conn=4&ProdID=173
so its more like some motherboard manufacturers messed up

btw i will take a 785G board over G45 anyday, why? dont need LPCM 7.1 but i do want dual stream decoding aka picture in picture, better quality on DVDs, better deinterlacing, and superior 3D performace, and superior 3D drivers

[USRF]Obiwan 6th August 2009, 14:09

since most of the users are going to be using it as a HTPC setup, won't they stream out the audio via optical out to their Über AV amp anyway?

sear 6th August 2009, 15:14

I'm not sure why you would bother with integrated sound these days. It has been and still is rather ****, even though it has improved in recent years. Even without the benefit of hardware acceleration, modern sound cards really do sound much better, and get way better signal-to-noise ratios than on-board. I've used integrated stuff before with my Sennheiser monitors and found them unusable because of how much feedback they picked up; I expect there are similar issues when plugging in and cranking up a huge surround system as well.

azrael- 6th August 2009, 15:33

The thing here is that the chipset apparently is incapable of handing over the 7.1 audio bitstream found on e.g. blu-ray discs via HDMI. Since 785G-based motherboards primarily will be used for HTPCs that's a pretty big feature missing.

Chocobollz 6th August 2009, 16:09

Quote:

Originally Posted by sear
I'm not sure why you would bother with integrated sound these days.

Because an additional add-on cards will take at least 1 slot? ;-)

Quote:

Originally Posted by sear
It has been and still is rather ****

IMO, it depends. If you're an audiophile, sure the sound cards will win, but if you're just an average billy kid joe, I don't think it's matter. An onboard sound will satisfy most peoples. To spot the difference in quality between a good sound cards & an onboard audio, you need to have the right equipments, in this case, a good speakers. And since most peoples won't bother with it, especially if they're not a computer enthusiast, it will not make any differences.

// Just my 0.02 bucks :P

Sparrowhawk 6th August 2009, 18:12

Quote:

Originally Posted by Chocobollz
Because an additional add-on cards will take at least 1 slot? ;-)

IMO, it depends. If you're an audiophile, sure the sound cards will win, but if you're just an average billy kid joe, I don't think it's matter. An onboard sound will satisfy most peoples. To spot the difference in quality between a good sound cards & an onboard audio, you need to have the right equipments, in this case, a good speakers. And since most peoples won't bother with it, especially if they're not a computer enthusiast, it will not make any differences.

// Just my 0.02 bucks :P

Or good ears. And lets not go there on the Verizon Math. :(

Lazarus Dark 7th August 2009, 04:13

Quote:

Originally Posted by sear
I'm not sure why you would bother with integrated sound these days. It has been and still is rather ****, even though it has improved in recent years.

We're talking about hdmi audio here. Bluray HTPC users want to stream pcm audio to their reciever. So long as the OS and onboard sound processor do not molest the stream, then you SHOULD be getting perfect Lossless audio to your reciever. As long as it passes the stream unmolested via hdmi, then the quality of onboard audio is completely irrelevant. If this chipset is not capable of that, then it is an automatic NO for most HTPC users.

B3CK 7th August 2009, 05:22

So when does BT get the upgraded equip to test such claims? Or will future reviews simply have warnings of "Mfgr claim of ** untested"?
Would like to see a cubicle converted to a one or two person theater room. Would give those of us that have, (or still are), had cubicle dreams of greatness an idea as to how such dreams would be brought to fruition.
Although, a nice HD projector, and a 4 sided cubicle, with the fabric walls might not make such a bad testing platform for speaker setups, projectors, wire management and other htpc related peripherals. Late night reviews of home theater equipment could help motivate certain journalists to "Go the extra mile/kilometer" to get to that deadline ontime.

LordPyrinc 7th August 2009, 23:59

I have a 7.1 capable sound card, but honestly would have a hard time finding a place to mount the side channel speakers. If I had a nice home theatre setup it would be cool, but I really don't watch movies on my computer.

Funny thing though, I have a 5.1 speaker setup on my computer for gaming, but only a 2.1 setup for my 40" LCD TV right now. Then again, I spend much more time gaming than I do watching tv or movies.