# How do we calculate MIPS here?

Status
Not open for further replies.

#### Tahmid

MIPS

Hi,
It varies from processor to processor(or microcontroller to microcontroller) depending on the architecture. E.g. Most PICs at 4MHz clock gives 1MIPS because these divide the clock by 4 and run. But an AVR at 4MHz gives 4MIPS as here there is no dividing of the oscillator. I'm not sure how much, but an 89C52 at 4MHz gives much less.

Hope this helps.
Tahmid.

#### millwood

MIPS

MIPS are a general indication of performance at a given clock speed. without understanding its limitations, it is fairly dangerous to use.

for example, not all instructions for pic/avr are 1-cycle instructions. plus, with more instructions than most pic, avrs can potentially get more done with fewer instructions.

then, when you compare 32-bit chips (most arm chips are around 1MIPS/Mhz) with 8-bit chips (PIC for example), it may take multiple instructions for an 8-bit chip to do the same as a 32-bit chip.

etc., etc.

#### 123music

##### Junior Member level 1
Re: MIPS

millwood said:
MIPS are a general indication of performance at a given clock speed. without understanding its limitations, it is fairly dangerous to use.

for example, not all instructions for pic/avr are 1-cycle instructions. plus, with more instructions than most pic, avrs can potentially get more done with fewer instructions.

then, when you compare 32-bit chips (most arm chips are around 1MIPS/Mhz) with 8-bit chips (PIC for example), it may take multiple instructions for an 8-bit chip to do the same as a 32-bit chip.

etc., etc.

I am bit confused with the notation MIPS/MHZ..

Let say if CPU clock is 8MHZ and instruction per clock is 1, then we get 8MIPS.
Now, can we say it is 1MIPS/MHZ???

Please correct me if i am wrong..

#### Tahmid

MIPS

Hi,
Like I stated above, it depends on the device. Pulling PIC and AVR as examples, in an AVR, at 8MHz, we get 8 MHz and so 1MIPS/MHz, but in PIC (most older ones), at 8MHz, we get 2MIPS and so 1MIPS/4MHz.

It depends on the architecture.

Hope this helps.
Tahmid.

Status
Not open for further replies.