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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Griswold - Monday, February 9, 2009 - link
"We're in the midst of a price war folks, and at a time when the global economy is looking a little shaky this actually works very well for us. Let's recap what's happened."That works very well for us until AMD, despite having a good product portfolio (this includes video cards), goes belly up thanks to this worldwide recession (a little shaky? Where have you been the last couple of months!?).And then what? Back to moon prices courtesy of Intel?
I hope not, but fear the worst. :(
lplatypus - Monday, February 9, 2009 - link
Why does the Ph II 940 system use only 4W more than the 810 at load? This is not consistent with TDPs (125W vs 95W). The HEXUS.net review found a 23W difference under load. Is something wrong here?Axloth - Monday, February 9, 2009 - link
I'd love to see detailed test of impact of cache size per core, because test results in this review are really weird. Something like x4 910 vs x4 810 vs x3 710. Pretty please with sugar on top...ET - Monday, February 9, 2009 - link
Needs more comprehensive testing, period. The results look really strange sometimes. Not only did the 810 sometimes outperformed the 910 significantly, but the 710 consistently beat the 910 in the gaming tests.(So far -- and I haven't read other reviews -- the 710 is looking like a good candidate to replace my aging X2 3800+.)
RadnorHarkonnen - Monday, February 9, 2009 - link
From the rumors ive seen in the web, this will be a pretty cheap cpu.Myt little brother is crying for My 4800 X2 (he always get free upgrades) with 4Gb DDR2.
Just one question, With a Stock VID 1.325 to 1.55 isn't that a little bit aggressive (even with good air cooling), for everyday operation ? I was hoping for a OC up to 3.6Ghz in decent voltage. 3.8Ghz Would be very good, but the voltage seems somewhat too large for day-to-day operation.
Thanks for reading, and replying if you have the time, of course.
Gary Key - Monday, February 9, 2009 - link
On our samples, starting around 3.5GHz you really had to ramp the Core VID. 3.6 required about 1.45V in the BIOS, with droop it was around 1.4375V real on this board. If the retail chips follow the 940, then I would say around 1.425V should be realistic for 3.6GHz on the right board. 1.55V is not outside of AMD's spec and is the limit they have found for air cooling. It is about the same limit we have noticed also for the most part, but these chips are designed to take a lot voltage if you keep them properly cooled.RadnorHarkonnen - Monday, February 16, 2009 - link
I'm already checking prices and availability for this hardware. I'll check the speed bump and the temp bump between 3.5 and 3.6. Thanks for the info Gary.duploxxx - Monday, February 9, 2009 - link
most run 3.4 ghz already on stock vcore@review, you state that there is no performance difference between ddr2-ddr3 but you didn't show anything? Anyhow official statement from AMD is that the ddr3 part bios is not fully ready yet, so I hope you will do a full review later.
Gary Key - Monday, February 9, 2009 - link
"@review, you state that there is no performance difference between ddr2-ddr3 but you didn't show anything? Anyhow official statement from AMD is that the ddr3 part bios is not fully ready yet, so I hope you will do a full review later."AMD told us a couple of weeks ago to concentrate on performance with the AM2+ boards since the AM3 BIOS releases were immature. I received several BIOS releases last week for our AM3 boards and felt safe enough to display numbers with them in the OC section today.
We are still testing and will have comparisons up in the near future. That said, we still have a list of requests back to the motherboard companies to fix. For the most part now, the AM3 boards are usable and clock well. I figure another BIOS spin or two and they should be good to go.
Also, in a best case scenario, AMD had performance improvements of 5% at best in memory bandwidth limited benchmarks with DDR3. Things might change with the 945 hits in a couple of months, but on these processors, there really are not any differences between DDR2 and DDR3 at this point.
Kaleid - Monday, February 9, 2009 - link
Power consumption and framerates at the max stable overclock?