Phenom vs Phenom II? What are the differences?

[f4phantom2500]

Thats Phenom I vs Athlon II. If you look at Phenom II, it beats the Athlon II, in games its a fair bit faster.

I know, IntelUser2000 was saying that Phenom I is slightly better than Athlon II, his reasoning being that Athlon II lacks L3 cache and that the main reason that Phenom II is faster than Phenom I is because of the additional L3 cache. But the way I see it, that doesn't make sense since the Athlon II appears to be overall slightly faster (although largely on the same level) as its Phenom I counterpart.

I find it odd, I always just assumed the Athlon II was closer to the Phenom II than the Phenom I. I've read reviews comparing the Athlon II X3 435 to the Phenom II X3 720, and there isn't much of a discrepancy. On the other hand, I also thought the Phenom II was a good step ahead of the Phenom I. I dunno. I honestly don't think that you can compare the Phenom and Phenom II without also considering the Athlon II.

 

[konakona]

Once you factor in the frequency ceilings of the two cpus, PhIIs are a good bit better. But I suppose you meant clock for clock...

 

[IntelUser2000]

*snip*

I honestly don't think that you can compare the Phenom and Phenom II without also considering the Athlon II.

I forgot to mention the L2 cache changes. I usually know about high-end CPUs and the low end kinda elude me.

The Athlon II lacks L3 cache yet has 1MB L2 cache per core. Phenom 9xxx had 2MB L3 but had only 512Kb L2 per core. If you go Phenom II, it goes back to Phenom 9xxx hierarchy with 512KB L2 per core + L3.

So that's how it manages to fair better than otherwise I guess.

 

[Jovec]

I forgot to mention the L2 cache changes. I usually know about high-end CPUs and the low end kinda elude me.

The Athlon II lacks L3 cache yet has 1MB L2 cache per core. Phenom 9xxx had 2MB L3 but had only 512Kb L2 per core. If you go Phenom II, it goes back to Phenom 9xxx hierarchy with 512KB L2 per core + L3.

So that's how it manages to fair better than otherwise I guess.

Athlon II x2s have 1MB L2 per core, the x3 and x4 have 512KB.

 

[SlowSpyder]

I had a Phenom 9850, it was not a bad chip... it just couldn't compete with what Intel had. In Windows Vista 64 I could only get it from the stock 2.5GHz to 2.7GHz (2.8GHz in XP 32bit), and that was with aftermarket cooling and extra voltage. This is a pretty big limitation in the eyes of enthusiasts, especially when Intel quads have already been available for some time and had no problems going well over 3GHz when overclocked.

My current Phenom II can hit 3.7GHz and does it in my old AM2+ motherboard I used with my Phenom 9850. With the other, newer Phenom II's, you can use them in many older motherboards and with your old DDR2 or go AM3/DDR3. I think that flexibility is attractive to some users as well.

 

[IntelUser2000]

athlon ii x2s have 1mb l2 per core, the x3 and x4 have 512kb.

nvm.

 

[Fayd]

Well it is between 10-20% (look at the Phenom II 940 3GHz vs Athlon II 635 2.9 GHz http://www.anandtech.com/bench/default.aspx?p=80&p2=122&c=1)

Seems huge, but then you notice one plays at 40 FPS and the other at 48 FPS (worst case) or one plays at 78 FPS and the other at 82 FPS.

And of course, at higher resolutions/higher IQ setting the difference won't be as noticeable.

Then again, in 2 years those Phenom II might still rock the newer games and people with Athlon II will need to change.

why would a percentile difference now make a monumental difference later?

for purposes of this thread: i got an x4 945 in combo with a 790X board... cause it was cheap.

 

[soccerballtux]

why would a percentile difference now make a monumental difference later?

for purposes of this thread: i got an x4 945 in combo with a 790X board... cause it was cheap.

Only benefit would be due to performance losses from branches. L3 helps with that.
Very few branches that can't be predicted efficiently in things like encoding. Games? Different story.

 

[IntelUser2000]

How can that be true? Aren't the Athlon II's essentially Phenom II's without any level 3 cache? If that were the case, wouldn't an Athlon II lose out to a Phenom at the same clock speed (assuming they have the same number of cores)? Unless I'm mistaken, this is not the case.

Ok, let me try this again. I think my first post and second post in this thread conflicts with each other.

Looking at both Xbitlabs benches and Anandtech's CPU charts, Phenom 9xxx and Athlon II X4's are largely similar. Both have cases where it beats the opposition, and there are cases where its similar.

The point of the first post was that it was largely clock speed changes that made them competitive. If it remained at 2.6GHz like original Phenom, it wouldn't have been. Core changes and cache latency changes were responsible for around half of the increase, and cache capacity changes, another half, maybe a bit less.

 

[Fayd]

Only benefit would be due to performance losses from branches. L3 helps with that.
Very few branches that can't be predicted efficiently in things like encoding. Games? Different story.

every bench i've seen shows a percentile benefit with L3. it's not a monumental benefit. so no, users of phenom II would be forced to upgrade around the same time as users of athlon II.

 

[soccerballtux]

every bench i've seen shows a percentile benefit with L3. it's not a monumental benefit. so no, users of phenom II would be forced to upgrade around the same time as users of athlon II.

Yeah/agree.

 

[GaiaHunter]

every bench i've seen shows a percentile benefit with L3. it's not a monumental benefit. so no, users of phenom II would be forced to upgrade around the same time as users of athlon II.

I agree with this as well, that is why I used the word maybe.

The truth is that if the original Phenom could have reached 3+ GHz when it was released it would have been competitive. But it couldn't so it wasn't.

But if you read this forums you will see some even call Athlons II X4 fake quads when they are just around the same performance as a Q6600.

 

[soccerballtux]

I agree with this as well, that is why I used the word maybe.

The truth is that if the original Phenom could have reached 3+ GHz when it was released it would have been competitive. But it couldn't so it wasn't.

But if you read this forums you will see some even call Athlons II X4 fake quads when they are just around the same performance as a Q6600.

I did too, I thought they were worse off without the L3.

Can they OC as high? Wouldn't you have to have a better board?

 

[GaiaHunter]

From what reviews and people say the Athlons II X4 can reach somewhere between 3.2-3.4GHz on stock voltage/cooling.

Anand was saying that the recent X4 635 he got would do 3.5GHz at stock.

 

[LoneNinja]

Since several people have brought up overclocking experiences with Phenom, Phenom II, and Athlon II, I'll share mine as well.

My Phenom 9850 easily hit 3.0Ghz for me, and only required an increase of .025V over stock. Bios reads voltage as 1.325 and cpuz shows 1.296. I never bothered to really try and push it further, 3.0 was my goal, but from what limited testing I've done voltage needs dramatically climb for even 3.1. I know 3.2 wasn't stable with 1.4 and I've never gotten windows to load at 3.3.

My Phenom II 940 was a bit of a dissapointment for me, I only managed to get 3.5Ghz which requires 1.375V. I know voltage can go a lot higher, but 3.6 isn't even 100% stable using 1.45V and I don't care to push voltage any higher for such a minor clock increase.

My Athlon II 630 easily hit 3.5Ghz using 1.45V, a .05 increase over stock. It'll probably go higher without much issue, I honestly haven't even attempted to get a max overclock out of this. I bought the 630 over the 620 simply because I wanted to run my fsb at 250 and this gave me a final clock of 3.5 instead of 3.25, worth a $10 difference to me.

 

[formulav8]

Wow IntelUser, alot of inaccurate info there, but your trying


Anyways, as some others has said the more notable changes are the die shrink which gave AMD room for Higher Clockspeeds, 6MB L3 cache, inclusion of a DDR3 memory controller, ect...

A couple of the tweaks they made to the DDR3 controller, they applied to the DDR2 controller. Cool and Quiet series 3. And I think all models now come with 2000/4000mhz htt/nb links? I do know that the PII based 5000+ only has 3200mhz links though, but the rest of the models is 2000/4000.?. Except for the 9850/9950 of the Phenom1, the other Phenom1 htt/nb links were 1800/3600mhz I think??.

They restructured the L3 cache. Increased its size by 3x, increased the L3 cache hitrate and reduced the L3 latency. So instead of a 32way L3 cache the new L3 cache is now 48way assoc. They also made the L3 cache 2 cycles faster. (Or in other words lowered latency by 2 cycles)

The L1 and L2 cache are the same. The L2 latency for both Phenoms L2's is 15 cycles (Thats the best I was able to calculate personally) and 16 way assoc.

Anyways, there are some other very minor changes. If I remember anymore i'll edit....

I would be curious though on what kind of performance difference it would make if AMD's L2 Latency was the same as Intels.... (AMD's is a 15 cycle L2 while Intels is a 10 cycle L2)



Jason

 

[Triskain]

I have to defend the original Phenom a bit here, since I own one . My 9950 reaches 3,0 GHz without ACC and with a lower than stock voltage, namely 1,2875V. After that it falls off a cliff because it needs much more voltage to get any further. But lets be fair here, not every Q6600 reached 3,6 GHz either, the later batches even had trouble reaching over 3,0 GHz without insane voltage.
I bought my Phenom for a very nice price and over a year later, it's still plenty fast for everything I might want to do.

 

[formulav8]

I guess I should say I have a 7550 X2 (Phenom1 DualCore - Stock is 2.5ghz) test cpu that has no problems hitting the 3ghz mark. ACC will give it another 100mhz or so.

Whats wierd is it unlocked the cpu to a quad (The clockspeed dropped to a wierd 1.6ghz for some reason) one time when Windows7 did a massive hault error and caused the system to reboot and then I didn't see it anymore as a quad since then :\


Jason