AMD's Phenom X3 8000 Series: Fighting Two Cores with Three?
by Anand Lal Shimpi on April 23, 2008 9:00 AM EST- Posted in
- CPUs
Power Consumption
For our power consumption numbers we only used CPUs that we actually had (rather than underclocking CPUs to simulate others).
Cool 'n' Quiet brings the Athlon X2's clock speed down low enough where, despite being made on a 90nm process, it actually draws less power than the 65nm triple and quad-core Phenom chips. The problem is that even the 6000+ doesn't run as cool as the rest of the Intel lineup here.
At the same clock speed, the power savings of a triple-core Phenom X3 vs. a quad-core X4 are tremendous. Unfortunately, despite much lower power consumption the X3 8750 still consumes more power than a much faster quad-core Core 2 Q6600. To make matters worse, the comparison will quickly shift to the Q9300 as availability increases and we already know how much better Intel's 45nm process is when it comes to power consumption.
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JarredWalton - Wednesday, April 23, 2008 - link
I've seen nothing to suggest a faster HyperTransport bus would help AMD much. You need to compare at the same CPU speed; if you raise the HT bus to 250 MHz that represents a 25% overclock of the CPU as well, so of course it helps performance a lot. Try comparing:Athlon X2 4600+ 2.4GHz
Run at 200 HTT and 12X CPU vs. 240 HTT and 10X CPU
Athlon X2 4800+ 2.5GHz
Run at 200 HTT and 12.5X CPU vs. 250 HTT and 10X CPU
(Note: the 12.5X multiplier vs. 10X may have an impact - half multipliers may not perform optimally.)
Athlon X2 5000+ 2.6GHz
Run at 200 HTT and 13X CPU vs. 260 HTT and 10X CPU
Now, the one thing you'll also have to account for is memory performance. At default settings (i.e. DDR2-800), you get different true memory speeds. The 12X CPU will end up at a true DDR2-800; the 12.5X will end up at DDR2-714 (CPU/7 yields 357MHz base memory speed); the 13X will result in DDR2-742 (again, CPU/7 yields 371 MHz base memory speed). For the "overclocked HT bus" setups, you'll need to select the same memory dividers to get apples-to-apples comparisons, which depending on motherboard may not be possible.
Unless you can do all of the above, you cannot actually make any claims that HyperTransport bus speeds are the limiting factor. I imagine you may see a small performance boost from a faster HT bus with everything else staying the same, but I doubt it will be more than ~3% (if that). HT bus only communicates with the Northbridge (chipset), and the amount of traffic going through that link is not all that high. Remember, on Intel that link to the chipset also has to handle memory traffic; not so on AMD platforms.
ghitz - Wednesday, April 23, 2008 - link
The e8400 performance/power usage is outstanding and will be great value once the G45 boards trickle in. I can't wait for those G45s!ap90033 - Wednesday, April 23, 2008 - link
So AMD STILL hadnt caught up. Thanks Good to know. Not that Im suprised....natebsi - Wednesday, April 23, 2008 - link
The bottomline is: AMD's newest CPU's are bested in nearly every single benchmark by an Intel CPU thats been out like, what, a year?I have no love/hate relationship with either Intel or AMD, but thats just sad. I predict many more losing quarters for them, though I don't know how many more they can take...
Griswold - Thursday, April 24, 2008 - link
Thanks for that null-posting.najames - Wednesday, April 23, 2008 - link
As a long time AMD only user, I just bought an Intel Q6600 on impusle from Frys.com for only $180. I was looking at a 780G solution and thought, I'll get the Intel quad and a similar Intel based solution for doing video processing work. Oops, I found out the only current Intel mATX is the G35 is from Asus, ONE BOARD, huge selection to choose from huh?I'll either sell/return the unopened CPU or buy a P35 board and graphics card. I could deal with a slightly slower AMD 9550 CPU and a better platform instead, tough choice.
strikeback03 - Wednesday, April 23, 2008 - link
I needed parts for a new system for the lab last week, I went with the non-integrated graphics and add-on card. Integrated graphics would have been fine for the application, but when the board plus card cost less than the ASUS G35 board (and are full-size ATX as well, which is useful) then the decision wasn't too hard.Staples - Wednesday, April 23, 2008 - link
Intel graphics have always been terrible. AMD definitely has the advantage for integrated graphics and even know their CPUs can not compete, I still find myself considering one just for their graphic options. I am glad that this review points it out bringing to light that Intel graphics are just not acceptable. Whether Intel will change is a big unknown, probably not.I find the added emphasis over the last year of power consumption a great one. With the price of energy these days, it is something I factor into my purchase. SSE4 and a lower power consumption is the reason I am holding out for a Q9450. Hopefully by the time it actually goes into mass production (hopefully in the next two months), a decent integrated option will be out for the platform.
0roo0roo - Thursday, April 24, 2008 - link
terrible? i used an intel 950 integrated graphics with some 1080p content, it decoded just fine with an e2200.derek85 - Thursday, April 24, 2008 - link
Terrible? Yes, terrible. Besides the lame hardware they can't even write proper drivers, see how many randering problems they have in the games.