Performance of tables slower than built in?

[Alex]

On Thursday, 23 May 2019 at 18:57:03 UTC, Ola Fosheim Grøstad 
wrote:
> On Wednesday, 22 May 2019 at 00:22:09 UTC, JS wrote:
>> I am trying to create some fast sin, sinc, and exponential 
>> routines to speed up some code by using tables... but it seems 
>> it's slower than the function itself?!?
>
> Not when I tried it with one of the online compilers, LUT is 
> 3-4 times faster on your tight inner loop, but I guess it 
> depends on the CPU.
>
> LUT should be very fast in long-running tight inner loops like 
> that once the cache is warm with such as small LUT that fits in 
> working memory (cache).

I've used very small LUT's like a length of 5 and it didn't 
significantly change anything.

Unless it is being hit hard at the start and that is skewing the 
results, it doesn't seem to be the issue.

I haven't tested this well but was just thrown off by the results 
as it should easily have been inverted and I expected quite a 
significant speed up(several factors) and not the reverse.