phenom II AM2+ vs AM3?

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intx
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phenom II AM2+ vs AM3?

Post by intx » Fri Feb 06, 2009 6:42 pm

which would you get for a quiet pc?

thanks!
Last edited by intx on Sun Feb 08, 2009 5:13 pm, edited 2 times in total.

lplatypus
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Post by lplatypus » Fri Feb 06, 2009 7:57 pm

The Phenom II 920 has a 125W TDP which is not ideal for a quiet PC.

Instead, check out the new 95W Phenom II models which are due to be launched on Monday.

Tephras
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Post by Tephras » Fri Feb 06, 2009 8:23 pm

My choice would be the Q9450, however, as lplatypus wrote, the Phenom II processors with 95W TDP is out in just a couple of days so I would like to read some reviews of the Phenom II 925 before making up my mind.

intx
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Post by intx » Mon Feb 09, 2009 12:25 am


lplatypus
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Post by lplatypus » Mon Feb 09, 2009 2:34 am

Do you mean that the Phenom II 940 system uses only four more Watts than the Phenom II 810 system at load? That is rather strange. I wonder if Anandtech did not load the CPU enough; here is a different review where the difference is 23 Watts under load:
http://www.hexus.net/content/item.php?i ... 13&page=11

jeekub
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Post by jeekub » Tue Feb 10, 2009 11:28 am

You get more headroom for upgrades later on if you go for Phenom II - such as DDR3's and quicker HT.

What's more, you can stick it in AM2+ socket MoBo and wait for the AM3 ones to drop the novelty price tag.

intx
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Post by intx » Tue Feb 10, 2009 6:50 pm

jeekub wrote:You get more headroom for upgrades later on if you go for Phenom II - such as DDR3's and quicker HT.

What's more, you can stick it in AM2+ socket MoBo and wait for the AM3 ones to drop the novelty price tag.
price difference is like $30.

vertigo
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Post by vertigo » Fri Feb 13, 2009 10:55 am

Just want to say, upgradeability can be misleading because the difference from what you have to the top model can seem substantial but may not look like much by the time you want to upgrade.

dhanson865
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Re: phenom II AM2+ vs AM3?

Post by dhanson865 » Fri Feb 13, 2009 11:41 am

intx wrote:which would you get for a quiet pc?

thanks!
If it were me I'd go for the cheapest one which makes me look at the X3 710 and 720.

* AMD Phenom II X3 720 - 2.8GHz, 7.5MB Cache - Black Edition in PIB at qty price of $145
* AMD Phenom II X3 710 - 2.6GHz, 7.5MB Cache - Available in PIB at qty price of $125

especially considering the X3 720 beats the X4 910 in most tests. (correction, meant to say it beats the X4 940 in some tests).

Use it in AM2+ for the low price now. If you want to upgrade wait for lower TDP parts to make the AM3 transition later when DDR3 is cheaper than DDR2. Until that price inversion occurs I'm not that interested in DDR3.
Last edited by dhanson865 on Wed Feb 18, 2009 9:18 am, edited 1 time in total.

joelmusicman
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Post by joelmusicman » Wed Feb 18, 2009 5:08 am

intx wrote: price difference is like $30.

The only true AM3 boards are $140+, or they are "AM2+/AM3" which means they are really AM2 boards (DDR2 memory, etc.).

REAL AM3 boards

Fakes

seemingly.random
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Re: phenom II AM2+ vs AM3?

Post by seemingly.random » Wed Feb 18, 2009 6:56 am

dhanson865 wrote:...

especially considering the X3 720 beats the X4 910 in some tests.

...
I noticed this also. This doesn't make sense. It has to be a bad test with s/w that doesn't use all cores.

---

Like others, I would think a 95 tdp would be much better than a 125 tdp. However, the power usage tests I've seen don't bear this out. In fact, under load, they seem to be about the same.

dhanson865
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Re: phenom II AM2+ vs AM3?

Post by dhanson865 » Wed Feb 18, 2009 9:04 am

seemingly.random wrote:
dhanson865 wrote:...

especially considering the X3 720 beats the X4 910 in some tests.

...
I noticed this also. This doesn't make sense. It has to be a bad test with s/w that doesn't use all cores.
No it makes perfect sense. Let me spell it out for you.

* AMD Phenom II X4 910 - 2.6GHz, 8MB Cache (as in 6MB L3 and 512K per core)
* AMD Phenom II X3 720 - 2.8GHz, 7.5MB Cache (as in 6MB L3 and 512K per core)

A. 2.8 GHz is higher than 2.6 GHz. Some bechmarks favor clock speed over number of cores.
B. Since the X3 has the same size L3 caches and one less core it has more L3 cache per core or in other words 6/4 is less than 6/3. Some benchmarks favor more cache per core.

Pick a reason but there are advantages to the X3 720 over the X4 910.

Further I made a mistake and meant to mention in that quote that it also sometimes beats the X4 940 which is 3.0 GHz. In those cases only B applies but we add C.

as per http://www.anandtech.com/cpuchipsets/sh ... i=3512&p=1 or http://en.wikipedia.org/wiki/List_of_AM ... _X4_series you can see

C. The Phenom II X4 940 is 3.0 GHz on the top end but also has a 1.8GHz clock for the Hypertransport bus. The X3 720 is only 2.8 GHz on the top end but uses a 2.0 GHz clock for the HT bus. This gives benefits on benchmarks that need faster access to memory.

In short there is no single CPU from AMD that is the fastest at all benchmarks. Given that I'm happy to grab the cheaper one that has the same large L3 and the faster clock for the HT.

joelmusicman
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Post by joelmusicman » Wed Feb 18, 2009 9:26 am

I believe that the better performance for the x3 has to do with its superior overclockability and more L3 cache per core. Therefore, single-threaded or dual-core only apps would do better on the triple core Phenoms.

dhanson865
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Post by dhanson865 » Wed Feb 18, 2009 10:27 am

joelmusicman wrote:I believe that the better performance for the x3 has to do with its superior overclockability and more L3 cache per core. Therefore, single-threaded or dual-core only apps would do better on the triple core Phenoms.
FWIW everything I said was from the standpoint of stock speeds. Overclocking is not something that is addressed by any of my posts in this thread.

Especially when underclocking and undervolting are more in the theme of SPCR than overlclocking is.

Tom.
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Post by Tom. » Wed Feb 18, 2009 12:01 pm

The 720 is great!

I'm using it with only a fanless Ninja 2, and almost no airflow (the Enermax MODU82+ doesn't produce that much airflow)
Stressed: < 55°C! :)

jobu
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Post by jobu » Sat Feb 21, 2009 12:05 am

What's a good AM2+ motherboard for a 720?

jeekub
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Post by jeekub » Sat Feb 21, 2009 2:38 am

If you're interested in ATX format I can recommend first hand Asus M3N-HT/HDMI.

From a week's usage experience i can tell it's good - full SpeedFan control over at least 3 headers and nice passive cooling, loads of expansion slots.

It's also supposed to undervolt/overclock really well, but I haven't yet found time to check it.

Nil Einne
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Post by Nil Einne » Sat Feb 21, 2009 5:37 am

jeekub wrote:You get more headroom for upgrades later on if you go for Phenom II - such as DDR3's and quicker HT.

What's more, you can stick it in AM2+ socket MoBo and wait for the AM3 ones to drop the novelty price tag.
Who cares about the mobos? The RAM is still way too expensive (presuming we're talking about real DDR3 AM3 mobos)...

jobu
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Post by jobu » Mon Feb 23, 2009 1:19 pm

jeekub wrote:If you're interested in ATX format I can recommend first hand Asus M3N-HT/HDMI.

From a week's usage experience i can tell it's good - full SpeedFan control over at least 3 headers and nice passive cooling, loads of expansion slots.

It's also supposed to undervolt/overclock really well, but I haven't yet found time to check it.
The reviews for that board are pretty low. Sounds like a number of people have had driver issues. What OS are you using?

Luminair
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Post by Luminair » Tue Mar 03, 2009 9:16 pm

Image

am3 and ddr3 DONT MATTER (just like dual and triple channel memory DOESN'T MATTER)

incorrect
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Post by incorrect » Tue Mar 03, 2009 9:28 pm

well as of right now i'd probably get the wonderfully cheap asus m3a78-em with an x3 710.

but i'd much rather wait until later this year and review the am3 boards and intel i5 cpus that will have launched by then. how long can you realistically hold out before buying a new system?

Olle P
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Post by Olle P » Tue Mar 03, 2009 11:26 pm

Luminair wrote:am3 and ddr3 DONT MATTER ...
... when it comes to computing performance.

There are other issues that would make me, the cheapskate, go for AM3 and DDR3:
- Future upgrades. Prolonging the life of the computer by adding more RAM and perhaps replacing the CPU two or three years from now. At that time it will be difficult and expensive to find an AM2+ CPU, and DDR3 will be cheaper than DDR2.
- Power/noise. DDR3 is more energy efficient than DDR2.

Cheers
Olle

Esben
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Post by Esben » Sun Mar 15, 2009 12:02 pm

The DDR2 vs DDR3 price difference is so small, it's a nobrainer for me, to skip the older platform. Fortunately the days of super expensive DDR3 are in the past now. I'm sure by the end of the year, most homebuilt computers will be made with DDR3.

biffzinker
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Re: phenom II AM2+ vs AM3?

Post by biffzinker » Sun Mar 15, 2009 2:18 pm

dhanson865 wrote: C. The Phenom II X4 940 is 3.0 GHz on the top end but also has a 1.8GHz clock for the Hypertransport bus. The X3 720 is only 2.8 GHz on the top end but uses a 2.0 GHz clock for the HT bus. This gives benefits on benchmarks that need faster access to memory.
That wouldn't be the hypertransport bus but the unicore (intergrated memory controller/L3 Cache.)

The only thing I didn't like about the Phenom II X3 720 is not all software uses the third core, and as a result it falls below the Core2 E8400 instead of being ahead when the third core is used.

DanceMan
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Post by DanceMan » Sun Mar 15, 2009 3:13 pm

Phenom II X3 720

There are reports of people enabling the fourth core on some of these. Worth checking out.

biffzinker
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Post by biffzinker » Sun Mar 15, 2009 3:38 pm

DanceMan wrote:Phenom II X3 720

There are reports of people enabling the fourth core on some of these. Worth checking out.
Only on an earlier production run though unfortunately. :(
It was earlier known that only chips belonging to 0904 (fourth week of 2009) batch of the processors would be able to respond to the mod successfully, but now, a fresh finding by German website Hartware.net suggests that even chips made in the 51st week of 2008 batch responded to the mod, and the fourth core could be enabled. Hartware.net used Biostar's TA790GX A2+ motherboard for the feat.

Greg F.
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Post by Greg F. » Sun Apr 12, 2009 3:16 pm


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