Author: William Henning
Editor: Howard Ha
Publish Date: Wednesday, April 23rd, 2008
Originally Published on Neoseeker (http://www.neoseeker.com)
Article Link: http://www.neoseeker.com/Articles/Hardware/Reviews/amd_phenom_8750/
Copyright Neo Era Media, Inc. - please do not redistribute or use for commercial purposes.
Today AMD is releasing the Phenom Tri-Core processor, and they were kind enough to send us a Phenom 8750 for testing.
The AMD Phenom 8750 runs at 2.4GHz (12x200) and is based on the same die as the quad core Phenom processors. As you may be aware, the initial launch of the quad core Phenom processors was plagued by the "TLB erratum" - a bug that could cause occasionally cause the processor to hang under certain heavy loads. Since then, AMD has come out with a new 'B3' stepping of the Phenom die, and this stepping apparently fixes the erratum - which is a very good thing as in our testing, the microcode based fix could have a significant impact on performance.
As we have covered the initial Phenom 9600, and the yet unreleased Phenom 9900, we will not cover the Phenom micro-architecture here; as there have been no changes since that time - other than the TLB fix.
So what is a Tri-Core processor?
It is either a quad core processor where one of the four cores failed AMD's quality control testing, and had the defective core disabled - and is now sold as a tri-core - or it is a quad core processor that had one of its working cores disabled in order to be able to market a tri-core SKU.
Regardless of how it became a tri-core part, I was interested to see how our 8750 would perform compared to not only the quad core Phenoms, but also a "Black Edition" dual core AMD 5000+ X2. I also threw in a comparison to a Core 2 Duo E6750, a 2.67GHz part - giving it a 267MHz speed advantage at stock speeds - to see how the tri-core would compare to an equivalently priced dual core Intel part. After all, AMD is trying to position the tri-core parts as a viable alternative to some dual core parts -- so let's see if they accomplished this goal with some testing.
In order to keep the testing as fair as possible, we will use the following test platforms:
Software used during testing consisted of the following:
Please note that we are showing overclocked results in all the charts - we are not holding you in suspense until the end of the article. The chart labels incorporate a lot of information about the test configuration. The first line shows the socket type and the model of the processor. Since all the processors shown -- beside the Phenom X3 8750 -- are dual-core devices, we did not specify that on the charts.
The second line shows the "FSB/HT clock rate" x "CPU multiplier" followed by the effective memory speed. All DDR2 tests were run at 4-4-4-12 timings unless otherwise specified.
At stock speeds the AMD 8750 beats the quad core Phenom 9600 slightly, and the AMD X2 5000+ quite soundly. It tied the faster Phenom 9900 and was only slightly beaten by the Core 2 Duo 6750.
When overclocked, it beat all the previous Phenom results.
The situation is not quite as good for Content Creation - but it is not bad either. Raw megahertz appear to count more here, and at stock speeds, the AMD 8750 is slighly beaten - but when overclocked, it does quite well.
Please note: We had to use a slightly newer Sandra for the Tri-Core as the 2007 version I'd used on the previous tests crashed - no doubt due to an unexpected number of cores. The results should be fairly comparable nevertheless.
Pretty much what I expected; The AMD 8750 Tri-Core was slightly beaten by the other Phenoms and the Core 2.
Sandra Memory Bandwidth
Not too shabby at all.
Take a look at the bottom of the chart. That's the impact the TLB bug could have on some software. Ouch - painful, isn't it?
Note how well the AMD Phenom X3 8750 tri-core does. At stock, it noticeably beats the Core 2 Duo E6750, and it compares well to the higher end Phenom results when you realize it has one less core.
The AMD Phenom 8750 Tri-Core had good memory read performance both at stock and overclocked, however it looks like the memory controller on the older AMD X2 5000+ is a bit better than the one on the newer chips.
Again, good performance, and outstanding performance by the older overclocked X2 5000+ Black Edition.
AMD chips with integrated memory controllers have normally done well with RightMark Latency, and the AMD Phenom 8750 Tri-Core is no exception.
I think we see some effect of the L3 cache here - the bandwidth figures for the AMD Phenom 8750 Tri-Core are excellent.
The Core 2 Duo's micro-architecture really shines here, the AMD Phenom 8750 Tri-Core does not do that well in the single threaded test.
Ah what a difference multi-core software can make! The AMD Phenom 8750 Tri-Core did quite well at the multi-threaded test, extremely well when overclocked , managing to almost catch the overclocked Phenom 9900!
The AMD Phenom 8750 Tri-Core does quite well for TMPGenc, especially the multi-threaded test.
No surprises here, the AMD Phenom 8750 Tri-Core did pretty well, and the third core definitely helped.
CineBench made good use of the third core, allowing the stock speed AMD Phenom 8750 Tri-Core to beat the stock speed Core 2 Duo E6750 on the multi-threaded run.
The AMD Phenom 8750 Tri-Core does not do that well here at stock or OC'd.
Call of Duty
Here the AMD Phenom 8750 Tri-Core performs quite well for a Phenom, but even the OC'd result is beaten by the stock Core 2 result.
The AMD Phenom 8750 Tri-Core did quite well at Doom 3 for an AMD chip.
Acceptable results here as well.
The stock Vcore on the AMD Phenom 8750 Tri-Core we received was 1.15V, but I had to push it to 1.37V in order to get the system stable at 3GHz.
We came very, very close to achieving a stable 3.12GHz overclock; and it may in fact be possible to run at that speed, however I was not willing to push the Vcore beyond 1.45V. Really, the only thing I had to do in order to overclock to 3GHz was to increase the "FSB" to 250MHz, and drop the HT multiplier to 7. The memory controller could use some better BIOS support, as most of the problems I encountered were with trying to run the memory at faster than about 850MHz at 4-4-4-12 timing, or faster than 1000MHz at 5-5-5-15 timing - and I was using PC8888 memory, rated for 1100MHz operation.
To get the system to run at 3GHz, we:
It was pretty easy.
I did try to stabilize the system at 3.12GHz, but gave up after spending hours on it.
With energy savings disabled, the system idled at 120W at stock speeds, rising to 166W when fully loaded; and when overclocked, it idled at 143W and rose to 230W under full load.
I was pleasantly surprised by how well the AMD Phenom 8750 Tri-Core performed compared to an AMD X2 5000+ and even a Phenom 9600. For office, encoding and multi-media tasks, it held its own at stock speeds against a higher clocked Core 2 Duo E6750 thanks to the extra core. As for the gaming results, before you get to dissapointed, note that all the gaming benchmarks were run at low resolution (640x480), with low detail settings, and no AA/AF in order to judge only the processor -- in a more realistic setting, the differences between the Core 2 and Phenom results would have been fairly insignificant at common gaming resolutions and settings (1280x1024, high AA, high AF) with a modern GPU (8800GT/9600GT or AMD HD3870/ HD3850).
Let's face it, AMD is in a tight spot competing against Intel right now - but this is, in many ways, a good situation for the consumer.
Simple. AMD has to market Phenom's (tri and quad core) based on price for performance, which means that they will tend to be cheaper than Core 2 processors. Mind you, this will help Intel's bottom line, allowing it to charge a premium for Core 2 Duo's and Quads until such a point as the market share for AMD Phenom's is too large for Intel's comfort, and Intel starts chopping prices more.
The question is, will the future 45nm "K10.5" CPU's allow AMD to ramp up frequencies to levels that will make Phenom's comparable to the fastest Core 2's?
Rumours are that "K10.5" micro-architecture was also tweaked for better performance...and I eagerly await testing it.
The bottom line: The AMD Phenom 8750 Tri-Core will provide an excellent bang for buck in business and media processing applications, and will perform "well enough" in gaming in order to keep AMD's market share. The X3 8750 is not an amazing processor, but it is a good one. For many people with older CPU's stuck in their AM2+ socket motherboards, the X3 8750 may be considered a price-effective choice for a possible upgrade.
Please do not redistribute or use this article in whole, or in part, for commercial purposes.