I found this helpful info. when researching differences between the 2 drugs. Valacyclovir has three to fivefold greater oral bioavailability (about 55 percent) than acyclovir; it then undergoes rapid and extensive first-pass intestinal and/orhepatic hydrolysis to yield acyclovir and L-valine [2,3]. Food does not affect absorption. Valacyclovir, at a dose of 250 mg four times daily, generates essentially the same acyclovir AUC (area under the curve, or exposure over 24 hours) as oral acyclovir at a dose 800 mg five times daily . Valacyclovir, at a dose of 1000 mg three times daily, produces a similar acyclovir AUC as intravenous acyclovir at a dose of 5 mg/kg every eight hours  http://www.uptodate.com/contents/valacyclovir-an-overview So if you do well on a dose of 500mg/once a day (like I do), you would need multiple doses totaling to 2000mg to achieve a similar effect. I'm not sure if the valtex still isn't better because you're getting a more steady dose of it over time vs. the acyclovir.