Help with Optimizing Voxel Code?

Hi guys, I've been working on optimizing some code for generating a voxel chunk (cubed, so x cubes by x cubes wide, each calculated, etc) and have no idea how to optimize it further. I know where the lag is (posted below) but can't figure out how do I optimize it, or at the very least hide of slow it is :p Here's the relevant code :

     public static byte calculateByte(Vector3 pos, Vector3 offset1, Vector3 offset2, Vector3 offset3)
     {
         Profiler.BeginSample("Gene");
         float clusterValue = calculateNoise(pos, offset2, 0.0001f);
         float biomeFloat = clusterValue * World.cWorld.biomes.Length;
         int biomeIndex = Mathf.Abs(Mathf.RoundToInt(biomeFloat));
         if (biomeIndex > 1)
         {
             biomeIndex = 1;
         }
         bf = biomeFloat.ToString();
         Biome biome = World.cWorld.biomes[biomeIndex];
         
         if (biomeDetailsSet == false)
         {
             //Debug.Log(biomeFloat);
             BiomeName = biome.name;
             grassEnabled = biome.grassEnabled;
             biomeDetailsSet = true;
         }
         float heightBase = biome.minHeight;
         float maxHeight = biome.maxHeight;
         float heightSwing = maxHeight - heightBase;
         float blobValue =  calculateNoise(pos, offset2, 0.01f);
         float mountainValue =  calculateNoise(pos, offset1, 0.01f);
 
         mountainValue += biome.mountainPowerBonus;
         mountainValue = Mathf.Pow(mountainValue, biome.mountainPower);
         //if (mountainValue < 0) mountainValue = 0;
 
         mountainValue = Mathf.Sqrt(mountainValue);
         byte block = biome.getBlock(Mathf.FloorToInt(pos.y), mountainValue, blobValue);
 
         mountainValue *= heightSwing;
         mountainValue += heightBase;
 
         mountainValue += (blobValue * 10) - 5f;
         if (mountainValue >= pos.y)
             return  block;
 
 
         Profiler.EndSample();
         return  0;
     }
 
     public virtual IEnumerator calculateWorldMap()
     {
         map = new byte[(byte)chunkWidth, (byte)chunkHeight, (byte)chunkWidth];
 
         Random.seed = World.cWorld.seed;
         Vector3 grain0Offset = new Vector3(Random.value * 10000, Random.value * 10000, Random.value * 10000);
         Vector3 grain1Offset = new Vector3(Random.value * 10000, Random.value * 10000, Random.value * 10000);
         Vector3 grain2Offset = new Vector3(Random.value * 10000, Random.value * 10000, Random.value * 10000);
         if (loaded == false)
         {
             for (int x = 0; x < chunkWidth; x++)
             {
                 for (int y = 0; y < chunkHeight; y++)
                 {
                     for (int z = 0; z < chunkWidth; z++)
                     {
                         if (y == 0)
                         {
                             map[x, y, z] = 6;
                         }
                         else
                         {
                             map[x, y, z] = calculateByte(new Vector3(x, y, z) + transform.position, grain0Offset, grain1Offset, grain2Offset);
                             if (grassEnabled)
                             {
                                 if (map[x, y, z] == 0 && map[x, y - 1, z] != 1 && map[x, y - 1, z] != 0)
                                 {
                                     map[x, y, z] = 1;
                                 }
                             }
                         }
                     }
                 }
                 yield return null;
             }
         yield return null;
         }
         f = bf;
         StartCoroutine(createVisualMesh());
 
         initialized = true;
 
         yield return null;
         chunksWaiting.Remove(this);
 
         if (chunksWaiting.Count > 0)
         {
             StartCoroutine(chunksWaiting[0].calculateWorldMap());
         }
         yield return 0;
 
     }

Any Ideas? It has been bottle-necking me for quite a while as this is the main factor that is slowing me down. Many Thanks :)

Edit: As requested I've now added the noise function and the noise generator. Noise Generator:

 // SimplexNoise for C#
 // Author: Heikki Törmälä
 
 //This is free and unencumbered software released into the public domain.
 
 //Anyone is free to copy, modify, publish, use, compile, sell, or
 //distribute this software, either in source code form or as a compiled
 //binary, for any purpose, commercial or non-commercial, and by any
 //means.
 
 //In jurisdictions that recognize copyright laws, the author or authors
 //of this software dedicate any and all copyright interest in the
 //software to the public domain. We make this dedication for the benefit
 //of the public at large and to the detriment of our heirs and
 //successors. We intend this dedication to be an overt act of
 //relinquishment in perpetuity of all present and future rights to this
 //software under copyright law.
 
 //THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 //EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 //MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 //IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 //OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 //ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 //OTHER DEALINGS IN THE SOFTWARE.
 
 //For more information, please refer to <http://unlicense.org/>
 
 
 namespace SimplexNoise
 {
     /// <summary>
     /// Implementation of the Perlin simplex noise, an improved Perlin noise algorithm.
     /// Based loosely on SimplexNoise1234 by Stefan Gustavson <http://staffwww.itn.liu.se/~stegu/aqsis/aqsis-newnoise/>
     /// 
     /// </summary>
     public class Noise
     {
         /// <summary>
         /// 1D simplex noise
         /// </summary>
         /// <param name="x"></param>
         /// <returns></returns>
         public static float Generate(float x)
         {
             int i0 = FastFloor(x);
             int i1 = i0 + 1;
             float x0 = x - i0;
             float x1 = x0 - 1.0f;
 
             float n0, n1;
 
             float t0 = 1.0f - x0*x0;
             t0 *= t0;
             n0 = t0 * t0 * grad(perm[i0 & 0xff], x0);
 
             float t1 = 1.0f - x1*x1;
             t1 *= t1;
             n1 = t1 * t1 * grad(perm[i1 & 0xff], x1);
             // The maximum value of this noise is 8*(3/4)^4 = 2.53125
             // A factor of 0.395 scales to fit exactly within [-1,1]
             return 0.395f * (n0 + n1);
         }
 
         /// <summary>
         /// 2D simplex noise
         /// </summary>
         /// <param name="x"></param>
         /// <param name="y"></param>
         /// <returns></returns>
         public static float Generate(float x, float y)
         {
             const float F2 = 0.366025403f; // F2 = 0.5*(sqrt(3.0)-1.0)
             const float G2 = 0.211324865f; // G2 = (3.0-Math.sqrt(3.0))/6.0
 
             float n0, n1, n2; // Noise contributions from the three corners
 
             // Skew the input space to determine which simplex cell we're in
             float s = (x+y)*F2; // Hairy factor for 2D
             float xs = x + s;
             float ys = y + s;
             int i = FastFloor(xs);
             int j = FastFloor(ys);
 
             float t = (float)(i+j)*G2;
             float X0 = i-t; // Unskew the cell origin back to (x,y) space
             float Y0 = j-t;
             float x0 = x-X0; // The x,y distances from the cell origin
             float y0 = y-Y0;
 
             // For the 2D case, the simplex shape is an equilateral triangle.
             // Determine which simplex we are in.
             int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
             if(x0>y0) {i1=1; j1=0;} // lower triangle, XY order: (0,0)->(1,0)->(1,1)
             else {i1=0; j1=1;}      // upper triangle, YX order: (0,0)->(0,1)->(1,1)
 
             // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
             // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
             // c = (3-sqrt(3))/6
 
             float x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
             float y1 = y0 - j1 + G2;
             float x2 = x0 - 1.0f + 2.0f * G2; // Offsets for last corner in (x,y) unskewed coords
             float y2 = y0 - 1.0f + 2.0f * G2;
 
             // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
             int ii = i % 256;
             int jj = j % 256;
 
             // Calculate the contribution from the three corners
             float t0 = 0.5f - x0*x0-y0*y0;
             if(t0 < 0.0f) n0 = 0.0f;
             else {
                 t0 *= t0;
                 n0 = t0 * t0 * grad(perm[ii+perm[jj]], x0, y0); 
             }
 
             float t1 = 0.5f - x1*x1-y1*y1;
             if(t1 < 0.0f) n1 = 0.0f;
             else {
                 t1 *= t1;
                 n1 = t1 * t1 * grad(perm[ii+i1+perm[jj+j1]], x1, y1);
             }
 
             float t2 = 0.5f - x2*x2-y2*y2;
             if(t2 < 0.0f) n2 = 0.0f;
             else {
                 t2 *= t2;
                 n2 = t2 * t2 * grad(perm[ii+1+perm[jj+1]], x2, y2);
             }
 
             // Add contributions from each corner to get the final noise value.
             // The result is scaled to return values in the interval [-1,1].
             return 40.0f * (n0 + n1 + n2); // TODO: The scale factor is preliminary!
         }
 
        
         public static float Generate(float x, float y, float z)
         {
             // Simple skewing factors for the 3D case
             const float F3 = 0.333333333f;
             const float G3 = 0.166666667f;
 
             float n0, n1, n2, n3; // Noise contributions from the four corners
 
             // Skew the input space to determine which simplex cell we're in
             float s = (x+y+z)*F3; // Very nice and simple skew factor for 3D
             float xs = x+s;
             float ys = y+s;
             float zs = z+s;
             int i = FastFloor(xs);
             int j = FastFloor(ys);
             int k = FastFloor(zs);
 
             float t = (float)(i+j+k)*G3; 
             float X0 = i-t; // Unskew the cell origin back to (x,y,z) space
             float Y0 = j-t;
             float Z0 = k-t;
             float x0 = x-X0; // The x,y,z distances from the cell origin
             float y0 = y-Y0;
             float z0 = z-Z0;
 
             // For the 3D case, the simplex shape is a slightly irregular tetrahedron.
             // Determine which simplex we are in.
             int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
             int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords
 
             /* This code would benefit from a backport from the GLSL version! */
             if(x0>=y0) {
                 if(y0>=z0)
                 { i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; } // X Y Z order
                 else if(x0>=z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; } // X Z Y order
                 else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; } // Z X Y order
                 }
             else { // x0<y0
                 if(y0<z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; } // Z Y X order
                 else if(x0<z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; } // Y Z X order
                 else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; } // Y X Z order
             }
 
             // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
             // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
             // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
             // c = 1/6.
 
             float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords
             float y1 = y0 - j1 + G3;
             float z1 = z0 - k1 + G3;
             float x2 = x0 - i2 + 2.0f*G3; // Offsets for third corner in (x,y,z) coords
             float y2 = y0 - j2 + 2.0f*G3;
             float z2 = z0 - k2 + 2.0f*G3;
             float x3 = x0 - 1.0f + 3.0f*G3; // Offsets for last corner in (x,y,z) coords
             float y3 = y0 - 1.0f + 3.0f*G3;
             float z3 = z0 - 1.0f + 3.0f*G3;
 
             // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
             int ii = Mod(i, 256);
             int jj = Mod(j, 256);
             int kk = Mod(k, 256);
 
             // Calculate the contribution from the four corners
             float t0 = 0.6f - x0*x0 - y0*y0 - z0*z0;
             if(t0 < 0.0f) n0 = 0.0f;
             else {
                 t0 *= t0;
                 n0 = t0 * t0 * grad(perm[ii+perm[jj+perm[kk]]], x0, y0, z0);
             }
 
             float t1 = 0.6f - x1*x1 - y1*y1 - z1*z1;
             if(t1 < 0.0f) n1 = 0.0f;
             else {
                 t1 *= t1;
                 n1 = t1 * t1 * grad(perm[ii+i1+perm[jj+j1+perm[kk+k1]]], x1, y1, z1);
             }
 
             float t2 = 0.6f - x2*x2 - y2*y2 - z2*z2;
             if(t2 < 0.0f) n2 = 0.0f;
             else {
                 t2 *= t2;
                 n2 = t2 * t2 * grad(perm[ii+i2+perm[jj+j2+perm[kk+k2]]], x2, y2, z2);
             }
 
             float t3 = 0.6f - x3*x3 - y3*y3 - z3*z3;
             if(t3<0.0f) n3 = 0.0f;
             else {
                 t3 *= t3;
                 n3 = t3 * t3 * grad(perm[ii+1+perm[jj+1+perm[kk+1]]], x3, y3, z3);
             }
 
             // Add contributions from each corner to get the final noise value.
             // The result is scaled to stay just inside [-1,1]
             return 32.0f * (n0 + n1 + n2 + n3); // TODO: The scale factor is preliminary!
         }
 
         public static byte[] perm = new byte[512] { 151,160,137,91,90,15,
               131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
               190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
               88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
               77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
               102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
               135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
               5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
               223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
               129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
               251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
               49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
               138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
               151,160,137,91,90,15,
               131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
               190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
               88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
               77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
               102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
               135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
               5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
               223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
               129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
               251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
               49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
               138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 
             };
 
         private static int FastFloor(float x)
         {
             return (x > 0) ? ((int)x) : (((int)x) - 1);
         }
 
         private static int Mod(int x, int m)
         {
             int a = x % m;
             return a < 0 ? a + m : a;
         }
 
         private static float grad( int hash, float x )
         {
             int h = hash & 15;
             float grad = 1.0f + (h & 7);   // Gradient value 1.0, 2.0, ..., 8.0
             if ((h & 8) != 0) grad = -grad;         // Set a random sign for the gradient
             return ( grad * x );           // Multiply the gradient with the distance
         }
 
         private static float grad( int hash, float x, float y )
         {
             int h = hash & 7;      // Convert low 3 bits of hash code
             float u = h<4 ? x : y;  // into 8 simple gradient directions,
             float v = h<4 ? y : x;  // and compute the dot product with (x,y).
             return ((h&1) != 0 ? -u : u) + ((h&2) != 0 ? -2.0f*v : 2.0f*v);
         }
 
         private static float grad( int hash, float x, float y , float z ) {
             int h = hash & 15;     // Convert low 4 bits of hash code into 12 simple
             float u = h<8 ? x : y; // gradient directions, and compute dot product.
             float v = h<4 ? y : h==12||h==14 ? x : z; // Fix repeats at h = 12 to 15
             return ((h&1) != 0 ? -u : u) + ((h&2) != 0 ? -v : v);
         }
 
         private static float grad( int hash, float x, float y, float z, float t ) {
             int h = hash & 31;      // Convert low 5 bits of hash code into 32 simple
             float u = h<24 ? x : y; // gradient directions, and compute dot product.
             float v = h<16 ? y : z;
             float w = h<8 ? z : t;
             return ((h&1) != 0 ? -u : u) + ((h&2) != 0 ? -v : v) + ((h&4) != 0 ? -w : w);
         }
     }
 }

Noise Function :

     public static float calculateNoise(Vector3 pos, Vector3 offset, float scale)
     {
         float noiseX = Mathf.Abs((pos.x + offset.x) * scale);
         float noiseY = Mathf.Abs((pos.y + offset.y) * scale);
         float noiseZ = Mathf.Abs((pos.z + offset.z) * scale);
         
         return Noise.Generate(noiseX, noiseY, noiseZ);
     }
 

Edit 2: I've now added a thread pool which works to some degree. However I'm still getting about half the frame rate I should (about 15fps when generating chunks). I'm completely new to multi-threading in unity so ideas in what could be causing the lag between threads would help a lot :)