It used to be fashionable to measure computer speed in MIPS (millions of instructions per second).

So I thought it would be interesting to:

- Find out how many XIPS (Excel Calculations per second) Excel could do on a modern PC.
- Then challenge people to guess how many calculations per second they thought Excel could do.

For my test I used Excel 2010 on my desktop PC, which is currently an Intel I7 870 2.93 GHz. This PC has 4 cores each of which can run 2 threads, so Excel 2010 could run 8 calculation threads in parallel if I set up the test properly.

In row 1 I entered =RAND() and copied the formula across to column Z.

Then I entered =A1+1 into A2 and copied the formula across to column Z, and then down to row 256000.

this gave me 6656000 formulae (6.6 million) in 26 independent calculation chains.

Then I switched to Manual Calculation mode and pressed F9 or Ctrl/AltF9 a few times to time the calculation (I was using FastExcel to time the calculations, if you don’t own FastExcel you can find the code for a simple calculation timer in my MSDN article on finding and prioritizing Excel Calculation Bottlenecks ).

**OK, so how many XIPS do YOU think Excel can do?**

- 1000 per second?
- 10000 per second?
- 100000 per second?
- 1000000 per second?
- More than 1000000 per second?

My PC calculated the 6.6 million formulae in under a second (the average was about 0.96), so my PC is rated at **6.9 MXIPS** (millions of Excel calculations per second).

Well I know its very simple formulae but WOW!!!

I was giving a talk a couple of years ago at the London Excel Users Conference on Improving Excel Performance, and I asked the audience the XIPS question: most of them thought the answer was in the tens or hundreds of thousands: nobody thought it was over a million.

So here is a question for future posts:

**If Excel can calculate formulae this fast how come my spreadsheet takes several seconds to calculate?**

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Great stuff Charles, looking forward to the answer in part 2.

Ross

“If Excel can calculate formulae this fast how come my spreadsheet takes several seconds to calculate?”

That’s a conundrum that’s earned me a very comfortable living for a good few years now, and I’m sure I don’t have anywhere near all the reasons, so I’m looking forward to seeing some things I’ve missed!

Kanwaljit, Hopefully the answers are worth more than the question!

Ross, Hopefully there will be many Part2s …

Mike, I am sure i don’t have all the answers either .