After some user feedback regarding the previous post about HT3.0 issues with the A12 revision from AMD's 780G, I contacted some people to set the record straight.
The issue will only apply to the Phenom 9100e and 9150e processors, which will run with an HT3.0 link at 1.6GHz.
With these CPUs, AGESA version 3.1.3 and up will automatically change the link to HT2.0 1Ghz. From what was disclosed now, all other will be able to use an HT3.0 link up to 2.6GHz, depending on the maximum speed supported by the CPU. This won't change in the B3 revision Phenom 9150e and Nvidia's MCP78 won't have the same issues with these low-end processors.
Some reviewers actually checked for the performance difference with both HT2.0 and 3.0 an it isn't good. For maximum performance in both integrated and hybrid modes, don't use the Phenom 91x0e or a K8 based processor, like the AMD Athlon X2, since both will have these performance losses.
I won't say you won't have problems later with other processors, but for now the issue has only been reported with these models. AMD had it pretty bad with the TLB issue: at first it was just an issue with the higher-clocked models but, after a while, a performance degrading fix was used for each and every B2 Phenom.
As posted before, the A13 revision of the chipset will fix these issues.
10 comments:
quote Tiago Marques: "The issue will only apply to the Phenom 9100e and 9150e processors, which will run with an HT3.0 link at 1.6GHz."
Why is that? Source?
It's inherent to the cpu, in the same way that the Phenom 9600 uses an 1.8GHz HT3.0 link instead of the top speed of 2.6GHz.
That information was provided together with what I got about the issue with the A12 revision of the 780G chipset.
quote "It's inherent to the cpu, in the same way that the Phenom 9600 uses an 1.8GHz HT3.0 link instead of the top speed of 2.6GHz."
wrong.
the HT3.0 = above 1000MHz and up to max 2600MHz
All cpu's within this range perform according to the HT3.0 specs.
http://en.wikipedia.org/wiki/HyperTransport
Inherent to the CPU, as in: those CPUs(9100e, 9150e) have a lower HT3.0 clock, of 1.6GHz, which is also the Northbridge clock. This is related to the core speed - the 9950 runs the HT clock higher than the 9550(2GHz instead of 1.8GHz).
The 1.6GHz HT3.0 clock has problems with these earlier revisions of the 780G, while CPUs with higher NB/HT clocks don't.
I'm planning on purchasing a Phenom 8650 3xcore ALONG with a 780g MB, DDR2 1066, Im basically Looking to get the most video quality out of the hardware, withouth running into any gimping issues, as described, so will my processor get full HD?
Hyper transport is listes as 3600,
Hi,
You want Full HD video or Full HD gaming?
If you just want full HD video decoding, you will be very well served with the 8650 and 780G. For regular H.264 and VC-1 you shouldn't need such a powerful CPU since the 780G can do hardware accelerated decoding - you will only need the 8650 for 1080p decoding in codecs like DivX and Matroska.
About the article, this 780G A12 issue doesn't happen with the 8650 CPU, so there will be no glitches of the kind.
Best regards
I only play world of warcraft, and i understand its not that graphic intensive, so primarily my goal is to get the best movie quality from netflix steaming and divx movies. I purchased the MB but went with a phenom II 2.6 tricore, runs great but had to load linux for time bieng as my windows install wont load w/o the old motherboard.. now would Vista x64 be a better choice for my movies/videos over an xp x64 os, and how would ubuntu compare in this situation to the windows os's.
Hi Kris,
World of warcraft should play fine. The X3 Phenom at 2.6GHz will give you very good performance with whatever revision you got of the 780G northbridge.
For Netflix/DivX, you shouldn't see much difference from XP 64 vs Vista 64 - although I would rather go with Vista, since XP64 never gathered much support even from MS itself, which won't be the case with Vista. My current Windows OS of choice is Server 2008 64bits.
Ubuntu, or Linux in general, should show better performance, although you shouldn't see much difference with that CPU. Most codec implementations for linux are better tuned, especially the ones compatible with proprietary formats like codecs from Microsoft, and even faster if you run an optimized Linux version like Gentoo.
I had an especially demanding 60FPS 720P video that couldn't run fine on a single core machine in Windows but would run without dropping frames in Linux - this was with a Gentoo install. The optimized packages were also helping but I really think you will always see better results in Linux.
Best regards
Ah, thanks so much I cant wait to install vista 64 monday night, as far as a graphics card goes, i have a 8600 gts, It seems fine but i'm not sure if its outdated and gimping me..any suggestions for a nice upgrade? btw its 256mb.
You're welcome.
If you don't feel you have performance issues in games, then you shouldn't need to upgrade.
If you need an upgrade, you have several good options right now:
- ATI 4830 (or 4770, will arrive this month)
- 9600GT/8800GT/9800GT 512MB
- GTS250 512MB/HD 4850 512MB
- ATI 4870 512MB
- ATI 4870 1GB
- GTX 260 core 216 896MB
The 4830 is my preference right now, over the 9600GT. Both are nice cards but the 4830 costs about the same with extra performance, while you still can find it in stores. The 4770 will be slightly better than the 4830. 9600GT is sub-$100 nvidia card, or an 9800GT if you can find it at that price.
The 4870 512MB is one of the best cards in the $150 range but if you have a monitor with more than 1680x1050 I would pick a card with more than 512MB.
Pick what you can afford as all the cards on the list are very good value for the money spent. Currently, it's one of the best times to be shopping for graphics cards (if you really need a new one).
Best regards
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