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Phenom II 720 vs C2D E8400

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March 16, 2009 9:52:35 PM

Hi,

I plan on upgrading my computer from an old pre-built system with an Athlon 64 x2 4000+ at 2.1GHz, and some crappy mobo.

I was originally going to buy an E8400 and this motherboard;
however, after reading through these forums a bit, a lot of people like the new Phenom II x3 720.

I wasn't going to upgrade past dual core until I get enough money for an i7 rig, but this processor has gotten very good reviews, an excellent price, overclocks a lot, and apparently has a fourth unlockable core.

I'm a gamer, I barely do anything else on my computer except convert the odd movie or do the occasional Photoshop project, so I was wondering which would be better for me? I plan to overclock (it will be my first time overclocking), and it seems that both are great overclockers. I will not be using DDR3 RAM (not for a while, anyways), and do plan to CF my HD4850 in a few months. I don't multi-task when I game, I turn EVERYTHING off except the essentials.

With the 720's lower processor price comes a higher mobo price, so they will end up costing roughly the same amount, so price is not a factor.

So, for pure gaming, which would be a better choice, the Phenom II 720 or the C2D E8400?
And if the 720 is your choice, what motherboard would you suggest getting?



My current rig:

Prebuilt mobo
AMD Athlon 64 x2 4000+ (2.1GHz)
4GB Kingston DDR2 800MHz RAM
Sapphire Radeon HD4850 1GB

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March 17, 2009 6:21:16 AM

If you want gaming and will OC your CPU, then don't unlock the 4th core, it was disabled for a reason. When those CPU's are manufactured they are tested for stability, if they find an unstable core on them then they disable it, so I doubt you will be able to overclock it at all, if it is even stable at stock.
March 21, 2009 6:58:11 PM

I'm in Canada and am using newegg.ca, and for some reason they don't have any CPU/Mobo deals, only CPU/HSF and CPU/Case deals.

Thanks shortstuff, for being the only one here to answer my main question.
March 21, 2009 9:49:11 PM

The 720 be is neck and neck with an e8500 in tomshardware benchmarks . Its really down to personal choice which way you go . I favor the AMD for the third core which will help in some situations.

You need a motherboard with a 780 or preferably 790 series northbridge chipset .
the southbridge [ sb] needs to be a 750 series to get best performance and potential overclocking .

Gigabyte and ASUS are the best brands IMO . But that biostar deal is well worth it for value . Pity about the US/canada isssue
March 25, 2009 8:27:38 AM

Jpain said:
Hello!

X3 720 vs E8400

1. http://plaza.fi/muropaketti/artikk [...] tion-am3,1

Yes! I know, but you can read the The table... Can you?


Have you clicked on your link?
Its a lot like another world ....but even weirder
March 25, 2009 2:29:37 PM

Jpain said:
Hello!

X3 720 vs E8400

1. http://plaza.fi/muropaketti/artikk [...] tion-am3,1

Yes! I know, but you can read the The table... Can you?


PLEASE post English speaking links, I'm in China and if I started linking to foreign sites, you wouldn't be able to figure it out either
March 27, 2009 8:17:37 PM

Jpain said:
Hello!

X3 720 vs E8400


http://plaza.fi/s/f/editor/images/X-2009032018074678056...

Yes! I know, but you can read the The table... Can you?


I can read your table :)  The problem is there is no test bed configurations and no testing methodology. When you compare different platforms you have to be ready to present the entire machine for each, so that we can see if the test was fair.
March 27, 2009 8:26:53 PM

shortstuff_mt said:
Why don't you look at the benchmarks for the games you play and let them speak for themselves so you don't get fanboys swaying your decision?

http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=351...

If you coose the Phenom II 720, I would check out this board:

GIGABYTE GA-MA790X-UD4P AM3/AM2+/AM2 AMD 790X ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $109.99


According to that link, the E8400 beats the AMD in all four games that were listed on there. E8400 ftw. :) 
March 27, 2009 8:59:40 PM

Why_Me said:
According to that link, the E8400 beats the AMD in all four games that were listed on there. E8400 ftw. :) 


According to the Tomshardware test the 720 scores higher [ by the same tiny margin ] in both Far Cry 2 and Crysis. It is also generally well ahead in multithreaded applications .
As Proximon has pointed out test methodology is important to the result . Far too often tests are set up that favor one chip or another and dont necessarily reflect real world usage

Performance wise the e8500 and 720 are very close , so the 720 is better value because of lower system pricing IMO
March 27, 2009 9:02:15 PM

Outlander_04 said:
According to the Tomshardware test the 720 scores higher [ by the same tiny margin ] in both Far Cry 2 and Crysis. It is also generally well ahead in multithreaded applications .
As Proximon has pointed out test methodology is important to the result . Far too often tests are set up that favor one chip or another and dont necessarily reflect real world usage

Performance wise the e8500 and 720 are very close , so the 720 is better value because of lower system pricing IMO



When you say "system pricing" are you talking about the motherboard and memory? btw, on those charts it showed the AMD's using alot more power (watts) than the Intels...why is that?
March 27, 2009 9:13:28 PM

More cores, more power consumption. There are other factors of course, such as the manufacturing process.
March 27, 2009 9:18:13 PM

Proximon said:
More cores, more power consumption. There are other factors of course, such as the manufacturing process.



In that case then we can assume that the AMD quads use the same amount of wattage as the Intel quads? Like for instance the Intel Q8200, Q8300, Q9400...
March 27, 2009 9:36:23 PM

The PIIs are similar I think. The old AMD quads suck up a bit more, since they are 65nm.

There's a great chart somewhere, kept up to date...
Bah, can't find it.

I know that you can't just look at the TDP. Someone had actual tests up last year. Perhaps someone else has the link.
March 27, 2009 9:41:47 PM

You do know that the AMD's Pll's clock down to as little as 800 MHz at idle . Much lower than the intels which seem to clock to about 60% at idle .

yes more cores = more power drain . Are you going to argue that no one should buy an intel quad because it has four cores?
March 27, 2009 9:52:56 PM

I'm not arguing or promoting anything. Why_me asked a question.

You also have to consider the motherboard however. If your processor has a memory controller built in, it might consume more power, but the board might consume less...

There was a great chart somewhere. I think it was a dutch site.
March 27, 2009 11:55:02 PM

Proximon said:
I'm not arguing or promoting anything. Why_me asked a question.

You also have to consider the motherboard however. If your processor has a memory controller built in, it might consume more power, but the board might consume less...

There was a great chart somewhere. I think it was a dutch site.



My comment was directed at why_me and his comment about the Phenoms using more power .

I should have been clearer about that .
March 27, 2009 11:59:58 PM

Outlander_04 said:
My comment was directed at why_me and his comment about the Phenoms using more power .

I should have been clearer about that .


Maybe you didn't read my post so well eh? I never argued anything on here...I asked a valid question, and Proximon answered it.
March 28, 2009 12:08:38 AM

Why_Me said:
Maybe you didn't read my post so well eh? I never argued anything on here...I asked a valid question, and Proximon answered it.


It was good of proximon to give an answer , but you asked me the question and so I answered it
March 28, 2009 12:57:40 AM

In my mind the decision is clear....

Core 2 Duo
-slightly higher stock frequencies
-less power consumption

Phenom II X3
-cheaper
-extra core
-newer platform
April 24, 2009 2:44:06 PM

I'm looking at the same build... comparing the 8400 vs the x3 720. I'm upgrading from old S939 A8N-SLI DX + Opteron 180. I will keep my 9800GTX+.

If I want to overclock the *** out of it, which is the best?

e8400 + Gigabyte EP45-UD3L + 2x2Gig 1066Mhz ddr2 Kingston KHX8500D2T1K2/4G set me at 394$ CAD

or

pII 720 + Gigabyte GA-MA790X-UD4P + 2x2Gig 1066Mhz ddr2 Kingston KHX8500D2T1K2/4G set me at 420$ CAD

I know the motherboard is a bit more featured for the AMD, but it's the cheapest 790-chipset mobo. I also know that the third core would be usefull sometime. I'm somewhat less happy to buy a 775 system as it's an already obselete platform as AMD will be releasing other CPU for a while. And a X4 955 might be nice later on.

[EDIT]
Just wanted to see if I go AMD, I'd surely go DDR3, it's not much pricer after all.

pII 720 + Gigabyte GA-MA790XT-UD4P + Corsair XMS3 DHX TW3X4G1600C9DHX 4GB 2X2GB PC3-12800 DDR3-1600 CL9-9-9-24 sets me at 458. A bit higher that I'd like, but would be a nice for a while.
April 24, 2009 3:08:33 PM

In those benchmarks the 8400 beats the 720 by ~0.3 frames persecond. I dunno about you but my eyes can't tell the difference ;) 

In some of the processer intensive benchmarks the 720 wins, in others the 8400, but only by fractions of a second.

Unlocking the fourth core is hit and miss. Most of the processors began as quad cores, but were found to have a bad core so AMD simply disabled it and sold them as the x3 with three good cores. Thus most of the fourth cores are bad and shouldn't be reenabled. However, because of the high demand for the x3, AMD didn't have enough processors with bad cores that they had to disable a good fourth core to make enough x3 720s. So who knows, you might get lucky. However, most reviews I've seen have very little luck unlocking the fourth core, and when they do its quite unstable and most of the time they can't overclock with the fourth core unlocked. But it doesn't hurt to give it a try, you might get lucky.

From what I've seen that 8400 can be overclocked to ~4.2ghz, and the 720 to ~4.0 depending on what forum, blog, article, or review you're reading. Either way you won't see any difference between the two, because at those speeds most games will be limited by your graphics card (depends on the game and what card you have also).

What size monitor are you using? Because unless its a 24" or bigger I don't see any reason to Crossfire. Save an extra $30-$50 and buy a 4870 instead, it will be worth it at lower resolutions, and it'll have a lot less power consumption being one card instead of two.

Now I am an AMD fanboy and IMO I would go for the PII x3 720, with a 790GX mobo, and an ATI card because of their great platform design. I also believe that when you're just running desktop applications the 790GX will use the integrated GPU it has on board and not your graphics card, thus saving a lot of energy (correct me if I'm wrong please).

However, my advice is this: find the best deal. If you can find a great C2D e8400 with a mobo for less than a 720 and 790GX mobo combo, go for it. Same goes if you find a cheaper AMD platform, because both are great processors and you'll be happy with either.
April 24, 2009 3:25:32 PM

it really depends on how long you're going to keep the system, if you just want a cheap upto standard gaming system before buying a Gulftown or the desktop version of Istanbul based pc in late 2009, early 2010 then get a e8xxx cpu, if you are keeping it for a good few years then the amd is the way to go.
April 24, 2009 3:56:30 PM

AMD has also been designing their hardware with upgrade ability in mind. For example the new AM3 CPUs can fit in the older AM2+ sockets. You lose the new features of AM3 but you get the newest hardware. Saves a lot of money from being forced to upgrade your mobo as well when you upgrade your CPU. Intel had the same strategy for a while with the 775, but plans to move everything to the new i7 socket (correct me if I'm wrong).
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