AMD's B3 Stepping Phenom Previewed, TLB Hardware Fix Tested
by Anand Lal Shimpi on March 12, 2008 12:00 AM EST- Posted in
- CPUs
The first B3 Stepping Phenom
We managed to get our hands on a 2.2GHz engineering sample B3 stepping Phenom:
AMD will begin shipping production B3 Phenoms later this quarter, presumably at higher clock speeds than the 2.2GHz - 2.3GHz launch parts. Our B3 sample was very similar to our B2 chip in that we could get it stable at 2.6GHz but didn't have much luck getting it to run comfortably any faster. We suspect that it'll take a move to 45nm before AMD can really start to push the clock speed on Phenom.
To get an idea of how much of a performance hit the software/BIOS TLB fix incurs we took a small selection of our normal CPU tests and ran with the patch enabled/disabled on a B2 stepping Phenom 9600 (2.3GHz):
| SYSMark 2007 | DivX | CineBench R10 | 3dsmax 9 | WinRAR | |
| AMD Phenom 9600 (B2 Stepping) - TLB Fix Disabled | 117 | 74.3 fps | 7396 | 7.20 | 1348 KB/s |
| AMD Phenom 9600 (B2 Stepping) - TLB Fix Enabled | 105 | 72.0 fps | 7031 | 6.47 | 367 KB/s |
| Performance Impact | -10.3% | -3.1% | -4.9% | -10.1% | -72.8% |
The smallest performance impact was a meager 3.1% reduction, but we suspect that 10%+ would be far more typical. WinRAR is a particularly extreme case where performance dropped by over 70%, which AMD indicated would happen given the heavy memory access nature of file decompression applications.
The new B3 stepping Phenom shouldn't perform any differently to a B2 stepping chip with the TLB fix disabled, but to confirm we ran the most extreme test once more:
512 256MB| WinRAR | |
| AMD Phenom 9600 (B2 Stepping) - TLB Fix Disabled | 1348 KB/s |
| AMD Phenom 9600 (B2 Stepping) - TLB Fix Enabled | 367 KB/s |
| AMD Phenom B3 @ 2.3GHz | 1357 KB/s |
As expected, all is good with B3. The TLB Fix option actually disappeared from the Gigabyte 780G's BIOS upon inserting a B3 chip, it's like the problem never existed.
Final Words
With the TLB erratum fixed in B3, AMD is one step closer to a competitive Phenom part. Unfortunately Phenom still suffers from low clock speeds and that's something AMD will be working on in the coming months. It will take a combination of higher clock speeds and very competitive pricing to really save Phenom.
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Griswold - Thursday, March 13, 2008 - link
You're a tech? Is that what they call callcenter jobs at Dell nowadays?Take your uneducated opionion and stick it where the sun doesnt shine, please.
whatthehey - Wednesday, March 12, 2008 - link
I believe the above "you stole this" comment is just spam. So just ignore it.As for the x64 and SPEC CPU stuff... x64 is becoming relevant, as 2GB PCs are common and 4GB setups are increasingly popular. The problem is, you can only fully realize the use of 4GB (or more) RAM if you run a 64-bit OS. Now we just need more 64-bit apps (Photoshop, I'm looking at you!) I'm personally running a Q6600 with 2x2GB and Vista 64-bit, and have no complaints other than the lack of 64-bit applications (not games - applications). And don't even think about bringing Xbox 360 into the picture... last I checked, you couldn't run Photoshop, Office, or any other real business application on an Xbox 360.
Regarding the TLB errata, we have at least two confirmed ways of causing this errata to rear its ugly head. Having done plenty of system testing, I can state that there are infinitely potential operations a CPU might be asked to perform. Multitasking in particular throws a wrench into the gears, because you can never test all the potential multitasking scenarios.
With two cases where the TLB bug comes up, you can be sure there are more. They may be rare -now- but we don't know what will happen going forward. Personally, I don't want a system where any time I experience a crash, I'm left to wonder, "Was that something wrong with the OS or application, or was that just the TLB error popping up in some new way?"
This is the AMD equivalent of the FDIV error Intel had back in the early Pentium days; unfortunately, the workaround has a far greater impact on performance. If you want to take a chance on the TLB error never affecting your system, you're welcome to do so. If that's the case, however, I'm wondering what you use your system for that makes quad-core even necessary.
Darkness - Wednesday, March 12, 2008 - link
AMDPhenom if you are going to write a review please do not cheat.This review was just copied and pasted from WWW.IMB.COM/UK.
We would like GENUINE reviews written by some one who has actualy tested this range.
You have not tested this personaly.
Please do not say you have as well all know you have not.
Please people the Phenom range is buggy I would not buy it untill AMD has sorted out these bugs.
I have read up on this range on many sites and all reviews say it is buggy and no anount of patches and updates are going to solve the problems for you.
Please wait before you decide to buy?
stmok - Wednesday, March 12, 2008 - link
Darkness if you're going to write feedback, please do not conduct fraud related activities.www.imb.com is a bank located in California.
DigitalFreak - Wednesday, March 12, 2008 - link
LOL. Not even a valid site. What a dipsh!t.nomagic - Wednesday, March 12, 2008 - link
Is this supposed to be some kind of joke?vijay333 - Wednesday, March 12, 2008 - link
dammit, who disabled the moron filter to the internet again?murphyslabrat - Wednesday, March 12, 2008 - link
If this was Dailytech, I would soooooo rate you up!fitten - Wednesday, March 12, 2008 - link
Any news on if they fixed the "Core2" problem?Brian23 - Wednesday, March 12, 2008 - link
I really wish you would do a clock for clock comparison of the Phenom to a Core 2 chip. That way we could see how the TLB fix affects which CPU is the prefered one in the lower cost segment of the CPU market.