Have I made a silly mistake here??

[CAT-THE-FIFTH]

A simple maths problem here for you Hexites.

You have two CPUs with two individual Super Pi scores.

CPU A = 23.775 seconds

CPU B= 29.219 seconds.

Am I right in saying that,CPU A is 18.6% faster than CPU B or outperforms CPU B by this percentage??

Is it also right to say that CPU B is 23% slower than CPU A??

I am only asking about the basic arithmatic in both cases.

I was having this conversation on another forum,and a few people said I was wrong about the maths in both cases?? Supposedly,CPU A outperforms CPU B by 23% according to those chaps NOT 18.6% like I calculated.

So am I loosing my mind or has a Moose has fallen on my head!!

The humble pie is going to quite large if I am wrong too!! Bloody alcohol!!

[billythewiz]

Your arithmetic is right, but I can't comment on the convention.

If cpu A gets something done in 3 and cpu B does it in 4, does that make B 33% slower and A 25% faster ?

[CAT-THE-FIFTH]

Well basically,they were telling me I did not know basic arithmetic,ie, in both cases I was wrong. I was not sure if I had ballsed up or gone mad or both.

[Terbinator]

Cannot un-see the results suggested by billythewiz!

OTOH, is it not because we don't have a '100%'/reference result for them to be compared to?

[CAT-THE-FIFTH]

Cannot un-see the results suggested by billythewiz!

OTOH, is it not because we don't have a '100%'/reference result for them to be compared to?

I get his point as the point of reference is difference in each case which is correct.

However, I am asking whether my sums are correct for both cases,ie, 18.6% faster and around 23% slower or not??

[jim]

% change = (new-old)/old

Just depends which direction you're going in.

All of your maths is right imo.

[cardav1981]

if i have my sums correct i believe the difference is 20.5% not sure about the faster or slower comment though heres the sum for calculating % difference
( | V1 - V2 | / ((V1 + V2)/2) ) * 100

[Whiternoise]

See special relativity.

Comparisons like this make much more sense if you have a C chip to compare both to.

[CAT-THE-FIFTH]

Here is what happened:
1.)I said CPU A was 18.6% faster than CPU B
2.)Then they(three people) said I was wrong and CPU A was 23% faster than CPU B
3.)I said that was not correct. CPU B was 23% slower than CPU A.
4.)They said I was wrong and came up with some other numbers

Hence,I cannot see what the heck they were going on about. I was not sure whether I was going mad and all of sudden could not do simple percentages any more(hence why I am asking this over here).

[CAT-THE-FIFTH]

C chip

Disposable Hemocytometers are a waste. The glass ones last longer,although if you drop one that is £100 down the drain(don't ask).

[Terbinator]

Just give us the link CAT.

[CAT-THE-FIFTH]

Just give us the link CAT.

Its in the BD thread.

[Random_guy]

Posted a full reply in the BD thread.

It's 23% faster I'm afraid, because speed is measured in workdone/ second, not in seconds, so effectively you have to flip the fraction over (see BD thread for derivation).

[Kumagoro]

I agree with random

I imagined it as how far you would get in one minute if it took you 29.219 seconds to do a mile and then 23.775 seconds a mile. It made more sense to me then.

[CAT-THE-FIFTH]

Posted a full reply in the BD thread.

It's 23% faster I'm afraid, because speed is measured in workdone/ second, not in seconds, so effectively you have to flip the fraction over (see BD thread for derivation).

I can see how the maths works out now but still a tad plastered. However,at least I will try to write the thought process which went through my head- I could be all wrong anyway and regret it when I wake up.

The problem is that quick and slow don't necessarily refer to speed only but to time too:

http://www.thefreedictionary.com/quick

"adj. quick·er, quick·est
1. Moving or functioning rapidly and energetically; speedy.
2. Learning, thinking, or understanding with speed and dexterity; bright: a quick mind.
3.
a. Perceiving or responding with speed and sensitivity; keen.
b. Reacting immediately and sharply: a quick temper.
4.
a. Occurring, achieved, or acquired in a relatively brief period of time: a quick rise through the ranks; a quick profit.
b. Done or occurring immediately: a quick inspection. See Synonyms at fast1.
5. Tending to react hastily: quick to find fault.
6. Archaic
a. Alive.
b. Pregnant.
n.
1. Sensitive or raw exposed flesh, as under the fingernails.
2. The most personal and sensitive aspect of the emotions.
3. The living: the quick and the dead.
4. The vital core; the essence: got to the quick of the matter.
adv. quicker, quickest
Quickly; promptly."

http://www.thefreedictionary.com/SLOW

"adj. slow·er, slow·est
1.
a. Not moving or able to move quickly; proceeding at a low speed: a slow train; slow walkers.
b. Marked by a retarded tempo: a slow waltz.
2.
a. Taking or requiring a long time: the slow job of making bread.
b. Taking more time than is usual: a slow worker; slow progress in the peace negotiations.
3. Allowing movement or action only at a low speed: a slow track; a slow infield.
4. Registering a time or rate behind or below the correct one: a slow clock.
5. Lacking in promptness or willingness; not precipitate: They were slow to accept our invitation.
6. Characterized by a low volume of sales or transactions: Business was slow today.
7. Lacking liveliness or interest; boring: a slow party.
8. Not having or exhibiting intellectual or mental quickness: a slow learner.
9. Only moderately warm; low: a slow oven.
adv. slower, slowest
1. So as to fall behind the correct time or rate: The watch runs slow.
2. At a low speed: Go slow!
v. slowed, slow·ing, slows "


The thing is I never mentioned speed though. In fact in my original post on the other plaice I had actually said "outperforms" with no reference to faster or slower. I think I should have kept to that description.

Lets say the A8=100 seconds and the A10=50 seconds

A10 vs A8

Using your formula,basically the A10 is 200% of the speed,ie,(((100/50)/(100/100))*100), of the A8.

However,using the method I used,the A10 CPU is 50% quicker than the A8. I never said speed ,I said quicker as it takes 50% less time(50 seconds) to do the task.

Lets go the reverse way.

A8 vs A10

Using your formula,basically the A8 is 50% of the speed,ie,(((100/100)/(100/50))*100), of the A10.

However,using the method I used,the A8 CPU is 100% slower than the A10,ie,takes 100% more time(50 seconds) to do the task.

Despite the diatribe,this might be all Moose droppings!

[jim]

So it's basically an argument over terminology? Seems a bit pointless to me.

If someone does something in 5 seconds, they're 50% quicker than someone who did it in 10 seconds. It may not be the only way of measuring a CPU's speed, but I don't see how it's an invalid approach.