Well, the problem is, it isn't exactly a multiplier wall at all. It's a frequency wall. For example, there are two walls...one with PLL overvoltage disabled and another with PLL overvoltage enabled. When you enable OV, you tend to gain around 400-500 mhz of possible mhz. Here's an example: You can replace this example with one more suitable for your current CPU:

If you find that you can load windows and run games at 4.9 ghz, 100x49, with PLL overvoltage disabled, but if you do X50, your board says overclocking failed, or boot loops and falls back to last settings (unless you switch PLL OV enabled), then what it means is that your CPU can't do 5 ghz with OV disabled, NOT that it can't do a x50 multiplier. You can test this by raising the BCLK and lowering the multiplier to x49, x48 or x47, to see if you can reach 5 ghz that way. What you will find is that your CPU will simply OC fail or boot loop around 4930 to 4960 mhz. You can quickly validate that by lowering the multiplier again and trying a slightly higher BCLK and see that it was not BCLK causing it, nor multiplier, and when you see that raising the vcore doesn't help in the least, you will have your answer.

Changing the BCLK/multiplier can let you squeeze in a little more mhz, but if you're too close to the wall, you may find strange things happening, like being unable to complete 3D, etc, even with enough vcore...