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Gul Dukat

CPU not running @ 2.0 Ghz

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scarecrow: FSB does not mean what you think it does, which is confusing people. FSB means front side bus. Ever since the 486DX/2 (remember that?) and the Pentium 266, almost all processors have run the front side bus at one speed and the CPU itself at another, as you can generally run the CPU's internal clock a lot faster than the FSB. As per http://www.techpowerup.com/cpudb/136/AMD_T...n_64_ML-37.html , the Turion ML-37's FSB speed is 200MHz.

 

This is entirely irrelevant to the question at hand, which does not involve the FSB at all. So please stop talking about FSB, you're just confusing the issue.

 

Gul, check your speed by checking the stuff in /sys/devices/system/cpu/cpu0/cpufreq/ . It's more accurate. cpuinfo_cur_freq is the current frequency, cpuinfo_max_freq is the max, cpuinfo_min_freq is the min, and scaling_governor tells you what frequency scaling strategy is currently being used.

Edited by adamw

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No, I mean that your CPU FSB is 1.6G, not 2.0G! The 2.0G is just AMD nomenclature...

At idle mode it goes at 800 Mhz.

Should be clear if you just consult the lappy manual.

 

Your "cat /proc/cpuinfo" was absolutely accurate- what's wrong about that?

 

 

the other question is are you running that test on the battery or with the adapter plugged in. MOST laptops now a days run at 1/2 speed (or less) when up plugged (power savings).

 

the other thing is that the 2GHZ rating by AMD is to give you an "Intel comparable" number, meaning that AMD feels that their CPU is optimized to the point that at 1.6GHZ (for example) it will run at a similar performence of an intel 2GHZ cpu.

 

I've run nothing but AMD's for the last 20 years (well ok my 1st upgrade was a NEC V20) and typically I have found that in day to day applicaton use they are almost always right.

 

j

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I don't think the information in your link is accurate, Adam.

Why not consult AMD directly? -_-

 

See here - clearly mentioning "Up to 1600 Mhz system bus" under AMD's patented "Hyper Transport" technology.

Edited by scarecrow

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Ahh, oke. That makes things a little clearer for me. But when I ran the command cat /proc/cpuinfo my laptop wasn't running on the battery, but was plugged in to the power.
That's why I don't trust that file. If you read that page I linked to earlier, you'll see I tried to puzzle things out with cpuinfo but realized that for me it didn't tell the (whole) truth.

 

And adamw's right, it's got nothing to do with the bus speed. Do we have a "red herring" smiley? I guess this will have to do: :wettrout:

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Gul, check your speed by checking the stuff in /sys/devices/system/cpu/cpu0/cpufreq/ . It's more accurate. cpuinfo_cur_freq is the current frequency, cpuinfo_max_freq is the max, cpuinfo_min_freq is the min, and scaling_governor tells you what frequency scaling strategy is currently being used.

Adamw, I don't think there' s a lot of difference between the command cat /proc/cpuinfo and the directory you gave me. As you can see here:

linux-ftxr:/sys/devices/system/cpu/cpu0/cpufreq # cat cpuinfo_cur_freq
800000
linux-ftxr:/sys/devices/system/cpu/cpu0/cpufreq # cat cpuinfo_min_freq
800000
linux-ftxr:/sys/devices/system/cpu/cpu0/cpufreq # cat cpuinfo_max_freq
2000000
linux-ftxr:/sys/devices/system/cpu/cpu0/cpufreq # cat scaling_governor
ondemand

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Hello Mindwave.

When AMD say their CPU frequency is 2.2Ghz then it means it runs at 2.2Ghz.

It has nothing to do with comparative Intel Frequencies. The comparative reference only is in the title of the cpu when it is called AMD3200 ( which runs at 2.2Ghz), meaning that it is as efficient as an Intel cpu of 3200Mhz (3.2Ghz). In other words AMD implied that an AMD cpu running at 2.2Ghz was as efficient as an Intel running at 3.2Ghz. It is believed that is one of the reasons Intel doesn't put so much emphasis on CPU speed now days because in reality ever greater CPU speed didn't really prove much. I see AMD no longer uses this type of naming system.

 

For others.

As I understand it, the FSB is a different thing again and is related to the intended speed of the memory. That is why the CPU speed and the FSB speeds ( which are both interconnected) are separately adjustable in the bios.

 

A whole range of different speed AMD CPUs can still have FSB frequency all set to the same frequency, for example 1600Mhz (1.6Ghz) which is the recommended speed for a whole range of Memory sticks of different values. A lot of newer memory is capable of running at up to 4.0Ghz while the CPU itself may still run at a lower freq.

 

As far as I can gather, in the Laptop cases where the CPU frequency is capable of being slowed to save battery power, the FSB frequency controlling Memory speed may or may not reduce frequency as well. This would depend on the type of bios used.

 

I think this is what AdamW is saying but if I have misunderstood him then he knows he is welcome to correct me.

 

Cheers. John.

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Thanks to Aussiejohn for your explanation.

 

Addition and correction about FSB, AMD ratings/numberings, etc...

 

Nowadays, AMD is using a different scheme for the cpu 'ratings' or numberings; for dual core cpu's with 1MB L2 cache, it's 2x the clock speed, so for a 4000+ amd64x2 with 1MB cache you have a 2 GHz cpu with 2 cores.

For 512KB of cache, substract 200 points, and for only 256KB another 200.

So a 2.6GHz AMD64x2 with 512KB of cache is named 5000+

 

 

As for the FSB, this used to be a really big deal before AMD put the memory controller on the CPU.

 

In the 'old' days (which are still with us for any Intel x86 chip), the cpu would use the FSB to connect to the northbridge, which would connect to the memory and the southbridge. AGP was also connected to the northbridge I think, to have faster memory access.

PCI, usb etc all connected to the southbridge, which also got to include LAN, audio, whatever else they could come up with.

 

 

In any case, the FSB speed makes a terrible difference if the memory is connected to the northbridge.

With recent AMD cpus this is not the case, so it becomes slightly less important. (One could argue that there's no longer a true northbridge nor a true FSB...)

 

The memory controller on the AMD cpu die (chip, whatever) is related to the clockspeed, but not with a fixed ratio, and with limited flexibility; it must have a 'fitting' multiplier, i.e. multiplication factor of the memory interface clockspeed versus the cpu clock speed.

Meaning: with a 2.4GHz AMD cpu your 800MHz DDR2 memory may run at 800MHz (multiplier of 3x), but a 2.6GHz AMD cpu will have it run at 742MHz. See also here for instance: http://www.hardwaresecrets.com/article/328

 

 

 

BUT the fact remains that an AMD cpu of 2.2GHz can and if necessary should run at 2.2GHz. My guess is that the /proc/cpuinfo data is collected once and not updated properly, so whatever the system said at that very moment is what this file will keep telling you.

I think that on my Intel laptop it does change, will have a look later....

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scare: Intel and AMD use various excuses to inflate the FSB speeds they quote, usually involving double- or quad- pumped memory speeds. But if you stick with the most accurate available definition of FSB (as artee noted, it's becoming a confused issue), 200MHz is the most accurate number to use. And *still*, as I noted, the FSB speed is entirely irrelevant to the issue. That's not what /proc/cpuinfo is quoting, nor anything else on the system that measures CPU speed.

 

gul: I would read that as saying the CPU is currently running at 800MHz due to scaling, but is capable of 2GHz. Depending on the scaling strategy being used it's entirely possible your system will run your CPU at 800MHz most of the time. Try doing something CPU intensive - compile something, run a CPU burning test app, whatever - and check cpuinfo_cur_freq again, see if it goes up to 2GHz. artee's explanation - that the reading is wrong - is also possible, but not the *first* explanation I'd pick.

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My opinion is that it doesnt matter as much the cpu and the fsb as long as they are decent, the slow down point usually is the hardrive, a fast hardrive would make running applications smoother. A fast cpu and fsb can only ammount to what the hardrive can read and write. High mhz ram sticks helps matters. Sorry for being off topic.

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