This directory contains versions of Rblas.dll linked against the ATLAS library (currently all of these are 32-bit versions): - Athlon64_SSE3 - AthlonXP - PII, PIII, P4, and PM (Pentium M) for various Pentiums - C2D for Core2Duo (but not necessarily corresponding QuadCore machines) - C2i7 for Core2-i7 optimized for 8 threads The Rblas.dll in PII, PIII and AthlonXP are linked against ATLAS 3.4.1, P4 and PM against ATLAS 3.6.0, Athlon64_SSE3_512k against ATLAS 3.7.37, C2D against ATLAS 3.9.11, and C2i7 against ATLAS 3.9.74. Rename ...\bin\i386\Rblas.dll and drop the new Rblas.dll into the ...\bin\i386 folder. Using the wrong version will either not work at all or work much slower than is possible. Note that using a different BLAS (than the standard one) may also result in numerical issues, errors, or even crashes. Please state in any bug reports that you are using non standard BLAS and always try the standard BLAS before reporting any errors.