Optimize the reading of a text file?

I've followed a lot of suggestions for optimizing graphics performance, and my projects currently sails along quickly and lightly in terms of rendering.

I do, however, have some overhead on loading that I'd like to minimize if possible. It comes down to reading a text file of objects and coordinates (this approach is questionable, but let's stick with it as a given).

I'm reading in a file that contains a subset of lines I'm interested in ("MARK" being the intial characters). Then, only a subset of these lines, I want to store coordinate information for - I check for the existence of the line type using a single character from the line string in a hash I populate at the start of the code.

I'm using builtin arrays for everything below.

I have the following:

if (textAsset == null) return;
reader = new StringReader(textAsset.text);
line = reader.ReadLine();

while (line != null)

    if(line.Substring(0,4) == "MARK")

        var identifier = Regex.Replace(line.Substring(13,4),"( )+","");

        if (lineType[identifier])


    vec *= Vector3(float.Parse(line.Substring(30,8)),float.Parse(line.Substring(38,8)),float.Parse(line.Substring(46,8)));*
 *vecSum += Vector3(float.Parse(line.Substring(30,8)),float.Parse(line.Substring(38,8)),float.Parse(line.Substring(46,8)));*
*<p>I'm clocking about 200 lines read per second.  I'm wondering if anyone sees anything in the above code that could be streamlined for a time gain?</p>*
*<p>Cheers, and thanks for reading this far!</p>*

First thing i see - you're parsing the vectors twice each - store the intermediary vector, then use it for vec *and adding to vecSum

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Second, you really should be using the overload of float.Parse that takes a CultureInfo object - otherwise on european computers, it'll have problems reading US/UK floats (and vice versa)

* *

Third, you're printing two items each time - that'll slow you down ridiculously (it has to print the current stacktrace to a file, as well as displaying it in the console), so remove those if you're testing performance