Which key design element changed in 2005 to drive continued improvements in computing capability?

The key design element that changed in 2005 to drive continued improvements in computing capability was the transition from single-core to multi-core processors.

Here are the steps explaining this transition:

1. Single-Core Era: Before 2005, most computer processors were single-core, meaning they had one central processing unit (CPU) that could execute one instruction at a time. This was sufficient for most tasks at the time, but as software became more complex and demanding, single-core processors started to reach their limits.

2. Need for More Power: As the demand for more computing power increased, simply increasing the clock speed (the speed at which a CPU executes instructions) was not enough. This was due to physical limitations and increased power consumption and heat generation.

3. Introduction of Multi-Core Processors: In response to these challenges, chip manufacturers like Intel and AMD started to produce multi-core processors. These processors have multiple CPUs (or "cores") on a single chip, allowing them to execute multiple instructions simultaneously. This design change was first introduced around 2005.

4. Continued Improvements: Since then, the number of cores in processors has continued to increase, driving improvements in computing capability. Multi-core processors are now standard in most computers, and many modern processors have four, six, eight, or even more cores.

5. Software Adaptation: Alongside this hardware evolution, software has also had to adapt. Modern software is often designed to take advantage of multiple cores, using techniques like multithreading and parallel processing to perform tasks more quickly.

In conclusion, the transition from single-core to multi-core processors around 2005 was a key design change that has driven continued improvements in computing capability.