Cracking the code

[angrybusdriver]

I'm trying to figure out the formula for AMD's PR on the Barton CPUs. (NO LOOKING IT UP, THAT'S CHEATING).

So far, with my lacking math skills, I have figured this much out.

Known:
3200 = 2200
2500 = 1830

(2500, 1830)
(3200, 2200)

(y2-y1) / (x2-x1)

(2200-1830) / (3200-2500)

370/700

f(x) = 370/700x + 510

Input at X is Assumed PR
Output at Y is Clockspeed

----------------

Now that all works, but I can't figure out how to reverse it so that you can input the clockspeed and get the PR. It works for 2500, 2600, 3200. So I'm assuming its reasonably accurate.

If someone gives me the equation, I'll slap it up with PHP and post the link so you can figure out your Barton's PR Rating.

Oh, and if everything is completely wrong, lemme know, cause as I said above, my math skills are poor.

 

[’m‚³‚ñ]

Originally posted by angrybusdriver
I'm trying to figure out the formula for AMD's PR on the Barton CPUs. (NO LOOKING IT UP, THAT'S CHEATING).

So far, with my lacking math skills, I have figured this much out.

Known:
3200 = 2200
2500 = 1830

(2500, 1830)
(3200, 2200)

(y2-y1) / (x2-x1)

(2200-1830) / (3200-2500)

370/700

f(x) = 370/700x + 510

Input at X is Assumed PR
Output at Y is Clockspeed

----------------

Now that all works, but I can't figure out how to reverse it so that you can input the clockspeed and get the PR. It works for 2500, 2600, 3200. So I'm assuming its reasonably accurate.

If someone gives me the equation, I'll slap it up with PHP and post the link so you can figure out your Barton's PR Rating.

Oh, and if everything is completely wrong, lemme know, cause as I said above, my math skills are poor.

So lets see...

(2200-1830) / (3200-2500)

2500 = 3200 = 2600
1830 = 2200 = 1900

Cross multiplication is close, but not exact. This method is off by about 100... I'm assuming that the reverse of your equation would be as well. Although, let's not assume that...

(y2-y1) / (x2-x1)

(2200-1830) / (3200-2500)

370/700

f(x) = 370/700x + 510

(a1 - a2) / (b1 - b2)

So... 700/370x - 960

I don't think these numbers are absolute. I pretty much pulled -960 out of my ass... It works, though. It's close, but not exact. Good luck.

Edit: Accredited the original equations to the original poster.

 

[K2Rage101]

This is 10th grade algebra.

I'm not checking your math, but to "reverse" your equation:
1. Subtract 510 from both sides
2. Multiply by 700/370 on both sides
3. Done

x = (y - 510)(700/370)

 

[Ravemaster Rich]

The PR ratings are pretty arbitrary mate. The 2500 and the 3200 have the same multiplier (11). The 2500 runs at 166FSB, the 3200 runs at 200. So, the processor and the FSB are 20% faster, meaning that the performance can't possibly improve by more than that, yet the PR rating increases by 28%. Yeah right.

Rich :¬)