Vc branch ready for testing

[JL VT]

On Tue, Sep 11, 2012 at 4:26 PM, Sven Langkamp <sven.langkamp at gmail.com>wrote:

> On Tue, Sep 11, 2012 at 12:21 PM, JL VT <pentalis at gmail.com> wrote:
>
>> I have overclockable memory but I'm fairly sure we are not bottlenecked
>> by memory, nowadays nearly nothing is.
>>
>> But I can still test, I can test at 1333 mhz and 1866 mhz (just an
>> example) and see if there is a chance. Is there any other way to check for
>> a memory bottleneck?
>>
> It's more like the oppsite. Most of the time the cpu is waiting for data.
> Your RAM is much slower than the cache, cache misses are usually really
> expensive.
>
> In the vc branch for example the masking for autobrush spends 2/3 of the
> time doing memcpy. That's just copying the color into the dab.
>

Before purchasing my RAM I looked at a long list of benchmarks on Tom's
hardware done on different types of software, and the only time the effect
of faster RAM was really noticeable was on artificial benchmarks.
Everywhere else, like games, encoding, video editing, it didn't go past 7%
speedup, even going from 1333 Mhz to 2100 Mhz, or single to dual, or dual
to quad channel. That's why I think it's not a memory problem. And if it
was, maybe we can program things differently; after all, if other graphical
software isn't affected by memory speed, why are we?.
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