I believe you don't drive through Ireland so much as you hurtle. Merriam-Webster defines hurtle as : to move rapidly or forcefully. And, quite honestly, when you are driving down roads like this you don't have to be going very fast to feel like you are going way too fast.
But I love driving in Ireland and can't honestly imagine seeing the country any other way. Many roads on your journey will be narrow and lined by hedgerows or stone fences and meeting another vehicle while traveling on them can require quick reflexes and the ability to squeeze your car as close to the edge of the road without causing damage. In some cases it may require you to actually back up to a wider part of the road so the oncoming traffic can pass.
Of course Ireland is not all scenic roads dotted with sheep farms and stone fences. You can quickly get from one end of Ireland to the other using very modern highways. For the Irish romantic (like me) it is a shame to see the modernization but for the Irish it is most welcome.
For the most part we stayed on the by-ways as discovering Ireland's uniqueness is often the best part of our trip. We saw many signs like this:
And let me just tell you that the road was just that sharply angled. Those signs don't lie.
My favorite road sign, by far, was this one just past the Cliffs of Moher on our way in to Doolin:
What you don't see is the sign just before it raising the speed limit to 100kph. It was quite funny.
Driving along the more scenic -and smaller- roads will definately take you longer in terms of time but it will also provide you many more memories than the fast paced highways.