How to upgrade computers (Socket 1155, Socket AM3+) so that there is noticeable acceleration when rendering video in sony vegas?

Question

Iron

Let me give you to start the configuration.
Intel Configuration:
CPU : Intel Core i3 3220 3.30GHz, Socket 1155 LGA
Fan : Box
Motherboard : ASUS P8H61-M LE R2.0
Northbridge Intel Ivy Bridge rev. 09
Southbridge Intel H61 rev. B3
UEFI BIOS
Memory :
1) 4096 MBytes PC3-10700 (667 MHz) Hyundai Electronics HMT351U6BFR8C-H9
2) 2048 MBytes PC3-10700H (667 MHz) Patriot Memory PSD32G13332
Memory Channels Dual
Max slots 2
Memory Frequency 664.9 MHz (1:5)
CAS# latency (CL) 9.0
RAS# to CAS# delay (tRCD) 9
RAS# Precharge (tRP) 9
Cycle Time (tRAS) 24
GPU: NVIDIA GeForce 9800 GTX+
Power Supply : 500W
HDD : Seagate ST31000524AS 1024GB SATA 6Gb/s 7200rpm 16Mb
OS : Microsoft Windows 7 (6.1) Professional 64-bit Service Pack 1 (Build 7601)
AMD Configuration:
CPU : AMD FX-6100 3.3 GHz, Socket AM3+
Fan : Box
Motherboard : ASUS M5A78L LE
Northbridge AMD 780G rev. 00
Southbridge AMD SB700 rev. 00
AMI BIOS
Memory
1) 2048 MBytes PC3-10700 (667 MHz) Kingston 99U5471-001.A01LF 2
) 2048 MBytes PC3-10700 (667 MHz) Kingston 99U5471-001.A01LF
Memory Channels Dual
Max slots 4
Memory Frequency 669.6 MHz ( ten past three)
CAS# latency (CL) 9.0
RAS# to CAS# delay (tRCD) 9
RAS# Precharge (tRP) 9
Cycle Time (tRAS) 24
Bank Cycle Time (tRC) 33
GPU : NVIDIA GeForce 210
Power Supply :
500W HDDs :
1 ) WD Caviar Blue 250 GB WD2500AAKX-19U SATA 6Gb/s 7200rpm 16Mb
2) WD Caviar Blue 250 GB WD2500AAKX-19U SATA 6Gb/s 7200rpm 16Mb
3) WD Caviar Green 500 GB wd5000azrx-00a SATA 500 GB wd5000azrx-00a OS
5 Microsoft Windows 7 (6.1) Ultimate Edition 32-bit Service Pack 1 (Build 7601)
*One of the SATA ports is not working on the board.
*Inexplicable fact: on an AMD computer, when connecting another hard drive (disconnecting the old ones), the computer cannot boot win7, both x64 and x86. A black screen with the windows logo passes very slowly, after which it reboots, the system does not detect the disk as bootable. On other computers, this disk starts up adequately.
Description :
There are two computers on intel and amd. What they are for: rendering in sony vegas, mostly frame-by-frame animation, but video also happens. Work in vector and raster editors.
Rendering takes place in MPEG 1080p, bitrate 25000, only on the CPU.
I experimented with rendering a one-minute video, and found out that an AMD-based computer runs many times slower, although I can’t explain this. The graphics card load is 0%, the processor is 100% loaded in both cases. The video card does not affect the speed in any way, I even set 1050ti, there are no differences from 210. The total download of the OP was within 3 GB. There is no throttling.
Based on the results of the experiments, I can conclude that the best strategy would be to improve the CPU. Do not touch the GPU at all, maybe increase the OP to 8GB. How changing the rest of the system will affect the rendering speed, I don’t know. So the questions came up :

1. does it make sense to change the HDD?
   
2. does it make sense to add the OP?
   
3. does it make sense to change the cpu without replacing the motherboard?
   
4. If there is an explanation about the facts that are incomprehensible to me, I will be glad.

What I got to:

1. For a computer with amd, install the DEEPCOOL GAMMAXX S40 cooler and overclock it to 4 GHz. Price 1.5k.
   
2. For a computer with intel, I would like to install an I5-2500k bu, overclock it and take a stronger cooler. But the motherboard is bad for this business, so this decision is in question. Price 4.5k + 1.5k.