The Phenom II X4 810 & X3 720: AMD Gets DDR3 But Doesn't Need It
by Anand Lal Shimpi on February 9, 2009 12:00 AM EST- Posted in
- CPUs
Lower TDPs, Faster un-core, DDR3 Support: The new Phenom II
All of the CPUs launching today are Socket-AM3 compatible. If you remember from my original Phenom II article, a Socket-AM3 CPU can work in both AM3 and AM2+ motherboards. I made a cute little compatibility matrix for you guys:
| CPU/Motherboard | Socket-AM2 MB | Socket-AM2+ MB | Socket-AM3 MB |
| Socket-AM2 CPU | Yes | Yes | No |
| Socket-AM2+ CPU | Maybe | Yes | No |
| Socket-AM3 CPU | Maybe | Yes | Yes |
AMD carefully engineered its AM3 memory controller allowing it to operate in both DDR2 and DDR3 modes. Any AM3 CPU can thus work in either a Socket-AM3 motherboard with DDR3 memory, or in a Socket-AM2+ motherboard with DDR2 memory. Backwards compatibility with original Socket-AM2 motherboards is up to the motherboard vendor, AMD does not validate any AM3 CPUs in regular AM2 motherboards.
The new Socket-AM3. Socket-AM2/AM2+ CPUs won't fit in here. But AM3 CPUs will fit in AM2+ boards.
All of the Socket-AM3 Phenom II CPUs are 95W TDP parts, compared to 125W for the first two chips that launched in January. The other notable change is that all of the AM3 CPUs run their un-core (North Bridge + L3 cache) at 2.0GHz instead of 1.8GHz like the AM2+ Phenom II processors.
Socket-AM3 Motherboards: Don't Bother Yet
I've had a Socket-AM3 motherboard here for a while but honestly the performance just isn't worth it. While it's taken a while to get stability up to par with AM2+, overall system performance remains unaffected. The Socket-AM2+ to Socket-AM3 transition looks a lot like the Socket-939 to Socket-AM2 transition we saw back in 2006.
A Socket-AM3 CPU (left) vs. a Socket-AM2 CPU (right) Note the missing pins on the AM3 chip.
Thankfully AMD gives you the option to ugprade whenever you'd like. You can buy a Socket-AM3 CPU today and use it in either an AM2+ board or an AM3 board, provided there's proper BIOS support. DDR3 memory is still more expensive than DDR2 and offers no real world performance advantage even at DDR3-1333 speeds.
Note that Socket-AM3 CPUs will only officially support one DIMM per channel running at 1333MHz. You'll need to run at 1066MHz speeds if you're running four DIMMs. When DDR2 and DDR3 memory reach price parity at the end of this year, AMD will be in a good position to make the transition. But if you're buying today, find a good AM2+ board and some cheap DDR2 memory.
The Test
| Motherboard: | Intel DX58SO (Intel X58) Intel DX48BT2 (Intel X48) MSI DKA790GX Platinum (AMD 790GX) |
| Chipset: | Intel X48 Intel X58 AMD 790GX |
| Chipset Drivers: | Intel 9.1.1.1010 (Intel) AMD Catalyst 8.12 |
| Hard Disk: | Intel X25-M SSD (80GB) |
| Memory: | G.Skill DDR2-800 2 x 2GB (4-4-4-12) G.Skill DDR2-1066 2 x 2GB (5-5-5-15) Qimonda DDR3-1066 4 x 1GB (7-7-7-20) |
| Video Card: | eVGA GeForce GTX 280 |
| Video Drivers: | NVIDIA ForceWare 180.43 (Vista64) NVIDIA ForceWare 178.24 (Vista32) |
| Desktop Resolution: | 1920 x 1200 |
| OS: | Windows Vista Ultimate 32-bit (for SYSMark) Windows Vista Ultimate 64-bit |
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Denithor - Monday, February 9, 2009 - link
Such as power consumption/heat charts for the dual core chips.(I mean, come on, these chips still hang with the quads in many cases, I want to see how much better they are from a power consumption standpoint - is it worth the upgrade to quad if you've got a speedy dual?).
To me it looks like the AMD chips give a lot better scaling when increasing the core count (X3 720 -> X4 920) than the Intel chips (e8400 -> Q9650). In most of the multi-threaded apps the AMD processors saw >95% increase (of the theoretical 33.3% possible) versus Intel with about 70-80% (of the theoretical 100%) on average. I wonder if this has to do with the fact the AMD chips are monolithic in design (more efficient interface among cores).
waffle911 - Monday, February 9, 2009 - link
The image of the "socket AM3" is actually of the AM2... it still has 940 pin sockets, not 938.JimmiG - Monday, February 9, 2009 - link
You need to change the "compatibility matrix" to reflect that an AM3 CPU will "maybe" work with an AM2+ mobo. Second-rate manufacturers like Asus will not release the needed BIOS updates for some of their older boards like the 790FX/SB600-based Asus M3A32-MVP Deluxe. If you have a SB7xx-based board and it's not made by Asus or another second-rate mobo manufacturer, the matrix is probably accurate.fishbits - Monday, February 9, 2009 - link
"We really have to applaud both companies here. Intel for responding so quickly and effectively; the 40% price drop on the Q9650 just made sense and now you can have a chip with 12MB of L2 cache for under $300 thanks to the Q9550."You're applauding Intel over this? To me, looks like they were screwing over customers with a gigantic artificial price premium. If it weren't for stepped-up competition from AMD, the price would have remained in the stratosphere. Intel is entitled to price however it wants, but I'm not going to applaud them for lowering prices only because another company exposed their gargantuan profit margin.
Juat a tiny taste of what would be to come if only Intel were left standing. If fanbois who wish AMD harm ever got their wish, there'd be no competitive pressure on CPU prices, and we see what Intel does in that position. We really need two healthy CPU makers in business.
Finally - Tuesday, February 10, 2009 - link
You know something's fishy, when a supposed article about a new AMD CPU starts with one full page of how Intel is the greatest evar... (and how much dropped their prices, which shall suggest to your mind that they are more interesting while they in fact go from Gargantuan to "normal" pricing for their products...)Maroon - Monday, February 9, 2009 - link
^agree^Why in the hell would you "applaud" Intel for price gouging? I know it's partly AMD's fault by not having truly competitive cpus for the last 2 years, but I'm not gonna give Intel props because they had to reduce prices to remain competitive in those price segments.
poohbear - Monday, February 9, 2009 - link
AMD Phenom II X3 710 is gonna be priced at around 125-135 i imagine, maybe even less, and for that price im sorry its a clear pick for those on a budget!! Its got 7.5mb cache, 3 cores, and will overclock to 3.6ghz if the 720 is any indication. Such sweetness. Any eta on em yet?BLaber - Monday, February 9, 2009 - link
As far as I have read on some other sites AMD sent an email along with the test samples to reviewers to test the cpus on AM2+ mobo for time being bcz AM3 mobo bios are having some performance issues.Nightstalker - Monday, February 9, 2009 - link
I don't understand the conclusion that there is no benefit to DDR3, when these CPU's were tested with DDR2. How about including results on these CPU's with both types of memory so we can see how they perform?Gary Key - Monday, February 9, 2009 - link
We will have additional DDR3/DDR2 results this week, we had AM3 BIOS releases coming until Friday night, the last one actually worked although it broke AOD and TurboV compatibility on the ASUS boards. We still cannot get DDR3-1866/2000 working. Of course, DDR3-1333 is the highest official support offered but we figure if it is in the BIOS then it should work.