Why is 945 so much worse??

[Paul22000]

Based on the chart here: http://www.cpubenchmark.net/high_end_cpus.html

The Phenom II X4 945 performs just barely a hair over the X4 810 (2997 vs 2988), both of which are FAR below the 955 and 940 (3580 and 3524, respectively).

What gives?

Why does the 945 perform so poorly???

I ask because the 945 has a great inexpensive motherboard combo @ $225 on newegg, but then I see these low performance benchmarks.

Any ideas?

 

[Outlander_04]

what actually is the passmark cpu benchmark?

what does it actually test ?

There so many other benches around that show the phenoms to be far beetter performers than intel quads higher up that list . that i suspect the bench is not representative of very much at all

notice the slow doggy Phenom 9600 complete with tlb error rates higher than an e8500 !
WHAT ?

 

[buzznut]

Ok, thats one synthetic benchmark. Do you plan on playing a lot of passmark?
JK. Sorry I couldn't resist.

I would take a look at the cpu charts here on toms, especially looking at the kinds of games you might be playing. Synthetic benchmarks are ok, but they (often) don't tell you much about real world performance.

I would expect most application performance to fall in between the 940 and 955. However those two processors have unlocked multipliers if you were going to attempt any overclocking. If not, then the combo deal may be your best bet.

I also understand that AMD is giving incentives w/ mobo combos with the new X4 965, which may also be worth a look.

 

[jimmysmitty]

Just for the two above, here is what it does:

CPU tests Mathematical operations, compression, encryption, SSE, 3DNow! instructions and more

http://www.passmark.com/products/pt.htm

Its a all around test.

As for why the 945 scores lower than the 940 I cannot say for sure. I really cannot say. i would think a faster CPU would do better. I mean the Intel ones make sense. The QX6800 is a bit below the QX6850 which there is a 70MHz difference and the FSB difference too.

but other than that it makes no sense. Even the X3 unlocked and the X4 910 does better than the 940.

then again the 940 was a DDR2 part and most of the newer ones are AM3/DDR3 parts. So possibly in those tests the DDR3 helps them out?

 

[JAYDEEJOHN]

What Id really like to know about all those bungholio synth tests are, say math in a synth, is that all it does at the time? If so, name a non bungholio anything that does JUST that?
Always, always place real world apps/games ahead of bungholio makrs

 

[masterjaw]

Conclusions based only on a single benchmark is ridiculous. Check out also other tests (both synthetic and real app) done for the 945 and see the big picture. I usually treat synthetic benches as second-rate given that no one would use a computer just to run benchmarks.

 

[Paul22000]

Ok, thats one synthetic benchmark. Do you plan on playing a lot of passmark?
JK. Sorry I couldn't resist.

I would take a look at the cpu charts here on toms, especially looking at the kinds of games you might be playing. Synthetic benchmarks are ok, but they (often) don't tell you much about real world performance.

I would expect most application performance to fall in between the 940 and 955. However those two processors have unlocked multipliers if you were going to attempt any overclocking. If not, then the combo deal may be your best bet.

I also understand that AMD is giving incentives w/ mobo combos with the new X4 965, which may also be worth a look.

Ok, so basically don't trust synthetic benchmarks too much then. But still, it's very odd that it has lower performance. There must be some reason.

Besides that, is there any performance difference between the 125W and the 95W versions of the X4 945 on Newegg?

125W - Phenom II X4 945 $169.99 http://www.newegg.com/Product/Product.aspx?Item=N82E16819103675
95W - Phenom II X4 945 $169.99 http://www.newegg.com/Product/Product.aspx?Item=N82E16819103696

Any other differences at all in performance etc?

I mean, if there are no differences, then why would anyone purchase the 125W? (Or why would AMD even produce it anymore?)

 

[loneninja]

AMD doesn't produce a 125W version anymore, it's just left over stock newegg is trying to sell. There is no difference other than one is slightly more energy efficient, probably only a few less watts under load because when the Phenom II first launched it barely drew over 95W, but was forced to use a 125W label because of it.

 

[Paul22000]

AMD doesn't produce a 125W version anymore, it's just left over stock newegg is trying to sell.

Ahhh, thanks.

One more question, I'm confused about the power chart posted in the recent 965 review:

http://www.tomshardware.com/reviews/phenom-x4-965,2389-10.html

Is that watts? As in the CPU under load uses almost 600 Watts *alone*??? Meaning you need a 900+ W PSU to run this beast in a normal computer??

If so, then what the heck is the point of putting "140W" on the CPU specifications?

 

[MarkG]

Is that watts? As in the CPU under load uses almost 600 Watts *alone*??? Meaning you need a 900+ W PSU to run this beast in a normal computer??

As that graph says, it's AC power going into the PC.

 

[megamanx00]

That link doesn't explain their test setup so it's hard to say. I'm guessing that they used high latency DDR 3 for the 945 while they used low latency DDR 1066 for the 940 thus giving the 940 a higher score. In the same AM2+ board and RAM the 945 should score the same as a 940. The 945 does a little better though in an AM3 board with good DDR3 RAM.

 

[Onus]

Here's a collection of lots of CPU benchmarks: http://www.anandtech.com/bench/default.aspx?p=36&p2=83

 

[Paul22000]

As that graph says, it's AC power going into the PC.

I'm not sure I follow?

Let me put it another way. How does the 590 on the graph correlate to the size power supply needed to run this CPU? Does it mean that you need a 600W Power Supply minimum JUST for running the CPU and nothing else?

 

[AdioKIP]

The chart shows AC power from the wall for the TOTAL system, not just the processor. Look at the test setup as a whole and think of it as you would need 600 minimum for running a similiar system.

 

[Onus]

No, that ENTIRE SYSTEM drew 590W from the wall. If the PSU was 82% efficient, the system was using 484W of power.
So, it would be running uncomfortably near its rated maximum, but a 500W PSU would have been enough.

 

[Paul22000]

The chart shows AC power from the wall for the TOTAL system, not just the processor.

Ohhhhhhhhhhhhhhhhh, ok, I see now.

If the PSU was 82% efficient, the system was using 484W of power.

Lost me again. Where did the 82% come from? And how is 500W enough if it requires 590W?

 

[AdioKIP]

The power you see listed for PSU's is there "Max" output, but for real world its more important to know there "Average" output for sustained load. Power supplies are rated by efficiency. The average is around 80-85%, a good PSU will be rated at 85% or higher usually. This means that you take the total output the power supply is listed as, say a 600 watt PSU, and multiply it by its rated percent, so a 600 watt PSU rated at 85% is 510 watts. The 510 is what the PSU is going to handle under constant load. With 600 being the "Max" it can draw, but it wont sustain that load (atleast not for long).

I've been building systems for 15+ years and one thing I've learned, no matter how tight your budget, if you have to skimp on a part NEVER skimp on the PSU...

 

[Paul22000]

The power you see listed for PSU's is there "Max" output, but for real world its more important to know there "Average" output for sustained load. Power supplies are rated by efficiency. The average is around 80-85%, a good PSU will be rated at 85% or higher usually. This means that you take the total output the power supply is listed as, say a 600 watt PSU, and multiply it by its rated percent, so a 600 watt PSU rated at 85% is 510 watts. The 510 is what the PSU is going to handle under constant load. With 600 being the "Max" it can draw, but it wont sustain that load (atleast not for long).

So why is it 590 * 82%?

Shouldn't it be then 590 / 82% = 720 needed?

I've been building systems for 15+ years and one thing I've learned, no matter how tight your budget, if you have to skimp on a part NEVER skimp on the PSU...

Does it waste a lot of extra electricity ($$) if I go overboard? Say for example get a 1000W. Or do PC's never use more than what they actually need?

 

[JAYDEEJOHN]

Converting from AC to DC, as a transformer, yes. Theres never a 1 to 1 scenario

 

[Paul22000]

Converting from AC to DC, as a transformer, yes. Theres never a 1 to 1 scenario

How much waste is there?

Example, if you have a 1000 W PSU and your system uses 600 W, is 400W wasted? Or some fraction of 400 W?

 

[AdioKIP]

So why is it 590 * 82%?

Shouldn't it be then 590 / 82% = 720 needed?

I've been building systems for 15+ years and one thing I've learned, no matter how tight your budget, if you have to skimp on a part NEVER skimp on the PSU...

Does it waste a lot of extra electricity ($$) if I go overboard? Say for example get a 1000W. Or do PC's never use more than what they actually need?

Multiply it, not divide. 590 * 82% (.82) = 483.8

 

[Onus]

The power you see listed for PSU's is there "Max" output, but for real world its more important to know there "Average" output for sustained load. Power supplies are rated by efficiency. The average is around 80-85%, a good PSU will be rated at 85% or higher usually. This means that you take the total output the power supply is listed as, say a 600 watt PSU, and multiply it by its rated percent, so a 600 watt PSU rated at 85% is 510 watts. The 510 is what the PSU is going to handle under constant load. With 600 being the "Max" it can draw, but it wont sustain that load (atleast not for long).

Sorry, not exactly. Assuming the PSU isn't an overrated piece of junk, its wattage is the total amount it can be expected to output (under given conditions, e.g. temperature). Depending on the quality of the PSU, it may or may not be able to sustain this for a long time, or at a high temperature. PSUs are most efficient when they are running at 40%-60% of their rated load. An 80+ PSU will have to be at least 80% efficient even at 100% load. If it is rated for 500W, when running at 100% load, it will pull 500 / 0.80, or 625W from the wall.

A Chokemax PSU loaded to 75% at room temperature will smoke and croak. An Antec SG-650 will put out 700W, 800W at 40C and laugh at you (at 870W, it will politely say "No can do," by quietly turning off, and no harm done).

 

[AdioKIP]

So why is it 590 * 82%?

Shouldn't it be then 590 / 82% = 720 needed?

I've been building systems for 15+ years and one thing I've learned, no matter how tight your budget, if you have to skimp on a part NEVER skimp on the PSU...

Does it waste a lot of extra electricity ($$) if I go overboard? Say for example get a 1000W. Or do PC's never use more than what they actually need?

How much waste is there?

Example, if you have a 1000 W PSU and your system uses 600 W, is 400W wasted? Or some fraction of 400 W?

A 1000 watt PSU is rated to Max at 1000, not constantly pull 1000. The amount of power it actually pull all depends on how much you have running in your system. A bigger PSU may draw more power then a smaller unit that is sufficient for your system but it would be nowhere near the full difference (i.e. in your example no 400 watts would not constantly be wasted).

 

[Onus]

A 500W PSU that is 80% efficient at 100% load will need 625W from the wall. A 650W PSU that is 85% efficient at the same 500W load will pull just over 588W from the wall; so in this case, the bigger PSU is actually wasting less power than the smaller one.

 

[JAYDEEJOHN]

Even at say half load, if its 500 watts at 80% itll take 270 watts to run and convert the 250 DC watts being used