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
Final Words
When AMD launched the Phenom II X4 940 and 920 I called it a True Return to Competition. With the rest of the lineup now more fleshed out, it's truly a return to competition. At every price point that AMD targets, it has produced a CPU competitive to Intel's offerings.
These new CPUs from AMD are good overclockers, good performers and they don't have any real drawbacks unlike their predecessors. The most interesting CPU is the Phenom II X3 720; at $145 its only Intel competitors are the Core 2 Duo E7500 and the Core 2 Duo E8400, both of which are dual-core CPUs. The extra core in the 720 can provide a clear advantage in well threaded workloads, not to mention that it's got 1.5MB of L2 cache and 6MB of L3 cache at its disposal. In applications where the third core isn't very useful then the 720 loses its performance advantage, which I suspect will be the majority of mainstream workloads.
The DDR3 question is easily answered: wait. While DDR2 isn't an option for Core i7, on all other platforms it just makes sense simply because of the high cost of DDR3 right now. By the end of the year we won't be having this debate as DDR2/DDR3 will be at the same price, but if you're building today don't even bother looking at DDR3 unless you're building Core i7. The performance benefits aren't worth it for Phenom II, so while AM3 sounds cool, it's not necessary today. Thankfully AM3 CPUs will work in AM2+ motherboards, so you aren't forced into a relationship with DDR3 if you're not ready.
On the CPU side, what we end up with is a buyer's market with tons of choices. At the high end, if you can manage, the Core i7 is simply in a league of its own. Honestly, if I were spending close to $300 on a CPU today I'd do my best to make up for the differences in platform costs and go with an i7 over any Core 2 or Phenom II alternative.
At the low $200 price point you have the Phenom II X4 940 vs. the Core 2 Quad Q9400 once again. The 940 wins in the vast majority of cases and gets the nod at $225. The Phenom II X4 920 isn't as clear cut of a winner, as it competes with the Q8300 or the Q9400 depending on whether you want to spend slightly less or slightly more. Against the Q9400 it loses, against the Q8300 it should be a closer call. At $195 I'd call the decision torn, but I'd lean towards Intel. The same is true about the Phenom II X4 810, it actually does a lot better than I expected it would given the reduction in cache size and at $175 it is competitive with the Q8200. The strongest showing in today's introduction seems to be the Phenom II X3 720. If you do any amount of offline 3D rendering work or use any other heavily threaded apps, you'll appreciate the third core, although in most other applications the E7500/E8400 are competitive despite only being dual-core parts.
Long term this strategy can't work for AMD. Intel can make 3 E7500s in the space that AMD makes a single Phenom II X3 720; the pricing pressure is great for the consumer, but again, I'm not sure how great it is for AMD in the long run.
Other than the clear cut i7 recommendation at the high end, thanks to aggressive price cuts and competitive CPUs, you can actually have your pick of which side you want to go with here. I'd say what it really boils down to is who can deliver the best retail pricing on CPUs and motherboards. Overclockers will probably prefer the Intel route as both Phenom II and Core 2 can overclock to similar levels, but Core 2 is faster at the same clock speed. Intel does have more room to drive prices down if it should so desire and perhaps it will, although I do worry about what will happen to AMD's Phenom II strategy when Core i5 arrives later this year. While Phenom II is competitive with Core 2, remember that it's an old architecture now. Turn to the Core i7 results for where AMD will need to start looking come this fall...
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7Enigma - Monday, February 9, 2009 - link
Ditto the power consumption at OC'd levels. I always get annoyed to see these fantastic OC results but then fail to see whether we've doubled the power consumption. It would certainly allow us to see a potential benefit if one or the other uses significantly less power under OC load conditions.Gary Key - Monday, February 9, 2009 - link
We will have power consumption and temps up tomorrow for the OC results along with a few benchmarks. It was difficult to get stable (true) volt readings with the X4 810 installed, so I spent my weekend with the DMM on the boards.Kaleid - Monday, February 9, 2009 - link
Great! Possible to also add difference with non-overclocked and overclocked power consumption at idle?7Enigma - Monday, February 9, 2009 - link
At the wall (total system) or just for the CPU? Do you mean the total system power was fluctuating with the 810? That seems really really wierd.Gary Key - Monday, February 9, 2009 - link
The power was fluctuating on the board at the Core VID side. I should have a BIOS spin tonight to fix it. The 720 was perfect but the 810 had a few problems that have been identified now.7Enigma - Monday, February 9, 2009 - link
*weird, please give us an edit function.OCedHrt - Monday, February 9, 2009 - link
Interestingly, the 810 vs 910, there is no real performance difference outside the margin of error. In some cases, the 810 is faster and in some, the 910 takes the lead. Something I noticed though is that the 810 is faster than the 910 at more times, and faster by a larger amount (~3% when it is faster) as well. Seems like the reduced cache does not actually hamper performance.Moorbo - Friday, April 24, 2009 - link
For most applications it seems you're correct that the smaller cache makes little difference. However if you look at the gaming performance the 2MB/core L3 cache of the 720 and 710 clearly makes a big difference despite their slower clock and lack of an additional core. What would the numbers look like with only two cores and 3MB/core and a higher clock?johnsonx - Monday, February 9, 2009 - link
indeed, the 710 is also often faster than the 910, but usually slower than the 810.I'm a bit surprised we the readers have to thumb through all the benchmark charts to see the 710/810/910 comparison. 3 Phenom II's at the same speed, one 'standard', one with less cache and one with a missing core; that is something AT should have dedicated a page to.
stmok - Monday, February 9, 2009 - link
Yeah, I noticed that as well. It looks like 4MB L3 cache is sufficient with Phenom II. (Any less, it'll start hurting...Any more, you're just wasting silicon space).